Health Education Systems Inc (HESI) A2 Exam Quiz: Percent Increase Decrease
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Percent Increase DecreaseQuestion 1 of 20

A pediatric medication dose is 15 mg/kg. The patient, who originally weighed 20 kg, has gained 10% of their body weight. What is the new total dose of the medication the patient should receive?

30 mg
300 mg
315 mg
330 mg
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Health Education Systems Inc (HESI) A2 Exam Quiz

Health Education Systems Inc (HESI) A2 Exam Quiz: Percent Increase Decrease

Practice Percent Increase Decrease in Health Education Systems Inc (HESI) A2 Exam with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Percent Increase Decrease, giving you a quick way to practice the rules, question types, and explanations that matter most for Health Education Systems Inc (HESI) A2 Exam.

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Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

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Question 1

A pediatric medication dose is 15 mg/kg. The patient, who originally weighed 20 kg, has gained 10% of their body weight. What is the new total dose of the medication the patient should receive?

  1. 30 mg
  2. 300 mg
  3. 315 mg
  4. 330 mg (correct answer)
Explanation: Pediatric dosing calculations require you to account for the patient's current weight, not their original weight, since medication effectiveness depends on the body mass that needs treatment. Start by calculating the patient's new weight after the 10% gain. The original weight was 20 kg, so a 10% increase means: 20 kg+(0.10×20 kg)=20 kg+2 kg=22 kg20 \text{ kg} + (0.10 × 20 \text{ kg}) = 20 \text{ kg} + 2 \text{ kg} = 22 \text{ kg} Now apply the dosing formula using the current weight: 15 mg/kg×22 kg=330 mg15 \text{ mg/kg} × 22 \text{ kg} = 330 \text{ mg} Looking at the wrong answers reveals common calculation errors. Choice A (30 mg) suggests someone multiplied the dose per kilogram (15 mg/kg) by only 2 kg—perhaps confusing the weight gain with the total weight. Choice B (300 mg) comes from using the original weight of 20 kg instead of the updated weight (15 mg/kg × 20 kg = 300 mg), which is a critical error since the patient's body mass has changed. Choice C (315 mg) appears to result from adding the weight gain incorrectly or making an arithmetic error in the final multiplication. The correct answer is D (330 mg) because it properly accounts for the patient's current body weight of 22 kg. Remember this key principle for HESI dosing questions: always use the patient's most current weight for calculations. Weight changes directly affect how much medication the body needs, so outdated measurements can lead to underdosing or overdosing. Double-check your weight calculations before moving to the dosing formula.

Question 2

The concentration of a disinfectant solution is increased from 0.5% to 0.75%. What is the percent increase in the concentration?

  1. 25%
  2. 33.3%
  3. 50% (correct answer)
  4. 75%
Explanation: When you encounter percent increase problems, you're calculating how much a value has grown relative to its original amount. The key formula is: percent increase = new value−original valueoriginal value×100%\frac{\text{new value} - \text{original value}}{\text{original value}} \times 100\% To solve this problem, identify your values: the original concentration is 0.5% and the new concentration is 0.75%. The actual increase is 0.75% - 0.5% = 0.25%. Now apply the formula: 0.250.5×100%=0.5×100%=50%\frac{0.25}{0.5} \times 100\% = 0.5 \times 100\% = 50\% Looking at the wrong answers: Choice A (25%) represents a common error where students calculate the absolute increase (0.25%) and mistakenly treat it as the percent increase without dividing by the original value. Choice B (33.3%) occurs when students incorrectly use the new value as the denominator instead of the original value: 0.250.75=33.3%\frac{0.25}{0.75} = 33.3\%. Choice D (75%) is the final concentration value itself, which some students might select if they confuse the question's intent. The correct answer is C (50%) because the concentration increased by 0.25 percentage points, which represents a 50% increase from the original 0.5% concentration. Remember this pattern: percent increase problems always require you to divide the change by the original value, not the new value. Watch for this distinction on math problems involving growth rates, dosage changes, or concentration modifications—it's a frequent source of errors on healthcare exams.

Question 3

A hospital's medication inventory shows that the stock of acetaminophen decreased from 2,400 tablets to 1,800 tablets over one month, while ibuprofen stock increased from 1,600 tablets to 2,080 tablets during the same period. What is the difference between the percent change in ibuprofen stock and the percent change in acetaminophen stock?

  1. 55% (correct answer)
  2. 50%
  3. 45%
  4. 40%
Explanation: First, calculate the percent change for acetaminophen: (1,800 - 2,400) ÷ 2,400 × 100 = -25% (decrease). Next, calculate the percent change for ibuprofen: (2,080 - 1,600) ÷ 1,600 × 100 = +30% (increase). The difference between the percent changes is 30% - (-25%) = 55%. Choice B (50%) results from incorrectly adding the absolute values. Choice C (45%) comes from calculation errors in the individual percentages. Choice D (40%) represents the sum of absolute values with computational mistakes.

Question 4

A patient's current weight is 170 pounds, which represents a 15% loss from their weight a year ago. What was the patient's approximate weight a year ago?

  1. 144.5 lbs
  2. 147.8 lbs
  3. 195.5 lbs
  4. 200.0 lbs (correct answer)
Explanation: Weight loss percentage problems require you to work backwards from the current weight to find the original weight. When you see that a patient has lost 15% of their weight, this means their current weight represents 85% of their original weight. To solve this, set up the equation: Current weight = Original weight × (100% - 15%). Since 170 pounds represents 85% of the original weight, you can write: 170=0.85×Original weight170 = 0.85 × \text{Original weight} Solving for the original weight: Original weight=1700.85=200 pounds\text{Original weight} = \frac{170}{0.85} = 200 \text{ pounds} You can verify this: 15% of 200 pounds is 30 pounds, so 200 - 30 = 170 pounds ✓ Choice A (144.5 lbs) represents a common error where students subtract 15% of the current weight (170) from the current weight, calculating 170 - (0.15 × 170) = 144.5. This incorrectly assumes the current weight is the starting point. Choice B (147.8 lbs) is also less than the current weight, which is impossible since the patient lost weight from their original weight. Choice C (195.5 lbs) might result from incorrectly calculating 15% of 170 and adding it to 170, or from computational errors in the division. Remember this key principle: when someone loses a percentage of their weight, their current weight represents what's left after the loss. Always identify what percentage the current weight represents of the original, then divide accordingly. Weight loss problems are common on the HESI, so practice setting up these "percent of original" equations.

Question 5

A patient's fluid intake target was 2.0 liters per day. After a medical review, this target was decreased by 25%. What is the patient's new fluid intake target in milliliters?

  1. 500 mL
  2. 1500 mL (correct answer)
  3. 1975 mL
  4. 2500 mL
Explanation: When you encounter fluid intake calculations on the HESI exam, you're being tested on your ability to perform percentage calculations and unit conversions—both critical skills in clinical practice where precise dosing and intake monitoring can be life-or-death matters. Let's work through this step-by-step. The original target was 2.0 liters per day, and it was decreased by 25%. To find 25% of 2.0 liters: 2.0×0.25=0.52.0 \times 0.25 = 0.5 liters. The new target is therefore 2.0−0.5=1.52.0 - 0.5 = 1.5 liters. Since the question asks for the answer in milliliters, convert: 1.5 liters×1000 mL/liter=1500 mL1.5 \text{ liters} \times 1000 \text{ mL/liter} = 1500 \text{ mL}. Looking at the distractors: Choice A (500 mL) represents only the amount of the decrease, not the new target—this catches students who calculate the reduction but forget to subtract it from the original. Choice C (1975 mL) might tempt students who incorrectly calculate a smaller percentage decrease or make arithmetic errors. Choice D (2500 mL) could trap those who mistakenly add 25% instead of subtracting it, thinking "change" always means increase. Study tip: For HESI percentage problems, always identify what you're finding first (the change amount or the final result), then double-check whether you need to add or subtract based on key words like "increased" or "decreased." Practice converting between liters and milliliters until it's automatic—fluid calculations appear frequently on nursing exams.

Question 6

A hospital cafeteria served 400 meals on Monday. On Tuesday, the number of meals served decreased by 15%. On Wednesday, the number of meals served increased by 20% from Tuesday's total. How many meals were served on Wednesday?

  1. 320
  2. 392
  3. 408 (correct answer)
  4. 420
Explanation: Multi-step percentage problems like this one require you to work through each change sequentially, using the result from each step as the starting point for the next calculation. Start with Monday's baseline of 400 meals. For Tuesday's 15% decrease, calculate: 400×0.15=60400 × 0.15 = 60 meals decreased, so Tuesday served 400−60=340400 - 60 = 340 meals. For Wednesday's 20% increase, you must use Tuesday's total (340 meals) as your new baseline—not the original 400. Calculate: 340×0.20=68340 × 0.20 = 68 meals increased, so Wednesday served 340+68=408340 + 68 = 408 meals. Answer A (320) represents a common error where students calculate 20% of the original 400 meals instead of Tuesday's reduced amount, getting 400−60−80=320400 - 60 - 80 = 320. Answer B (392) results from incorrectly applying the Wednesday increase to the original Monday total: 400−60+52=392400 - 60 + 52 = 392. Answer D (420) comes from first increasing Monday's total by 20%, then decreasing by 15%, which reverses the order of operations. The key trap here is using the wrong baseline for subsequent percentage calculations. Each percentage change must be applied to the most recent total, not the original starting value. When you see sequential percentage problems on the HESI, always write down each step's result before moving to the next calculation—this prevents you from accidentally referring back to an earlier number.

Question 7

A patient is advised to reduce their daily calorie intake of 2,200 calories by 20%. After one month, they are further advised to reduce the new daily intake by another 10%. What is the final target daily calorie intake?

  1. 1540
  2. 1584 (correct answer)
  3. 1760
  4. 1980
Explanation: Multi-step percentage problems are common on the HESI exam and test your ability to apply percentage reductions sequentially. The key insight is that each percentage reduction applies to the current amount, not the original amount. Let's work through this step-by-step. Starting with 2,200 calories, the first reduction is 20%. Calculate this as: 2,200×0.20=4402,200 × 0.20 = 440 calories to remove. This gives us 2,200−440=1,7602,200 - 440 = 1,760 calories after the first month. The second reduction of 10% applies to this new amount of 1,760 calories, not the original 2,200. Calculate: 1,760×0.10=1761,760 × 0.10 = 176 calories to remove. The final target is 1,760−176=1,5841,760 - 176 = 1,584 calories. Looking at the wrong answers: Choice (A) 1,540 likely results from calculation errors or applying both percentages incorrectly. Choice (C) 1,760 is the intermediate value after only the first reduction—this traps students who forget about the second 10% reduction. Choice (D) 1,980 represents applying only a 10% reduction to the original amount, missing the sequential nature entirely. The most common mistake is applying both percentages to the original amount (thinking 30% total reduction), but percentage reductions are cumulative and sequential. Always apply each new percentage to the most recent value, not the starting point. When you see multi-step percentage problems on the HESI, work through each step methodically and double-check that you're using the correct base amount for each calculation.

Question 8

A liquid medication contains 250 mg of active ingredient in a 5 mL solution. If the amount of active ingredient is increased to 300 mg while the total volume remains 5 mL, what is the percentage increase in the medication's concentration?

  1. 16.7%
  2. 20.0% (correct answer)
  3. 25.0%
  4. 50.0%
Explanation: When you encounter percentage increase problems in dosage calculations, you're working with concentration changes that directly impact medication safety and efficacy. The key is calculating the original concentration, the new concentration, then finding the percentage change. Start by finding the original concentration: 250 mg5 mL=50 mg/mL\frac{250 \text{ mg}}{5 \text{ mL}} = 50 \text{ mg/mL}. Next, calculate the new concentration: 300 mg5 mL=60 mg/mL\frac{300 \text{ mg}}{5 \text{ mL}} = 60 \text{ mg/mL}. To find percentage increase, use the formula: new value−original valueoriginal value×100%\frac{\text{new value} - \text{original value}}{\text{original value}} \times 100\%. Substituting our values: 60−5050×100%=1050×100%=20%\frac{60 - 50}{50} \times 100\% = \frac{10}{50} \times 100\% = 20\%. This confirms answer B is correct. Answer A (16.7%) likely comes from incorrectly using 300 mg as the denominator instead of the original concentration. Answer C (25.0%) might result from miscalculating the concentration difference or using faulty mental math. Answer D (50.0%) represents a common trap where students incorrectly calculate 50100×100%\frac{50}{100} \times 100\% by mixing up the numerator and denominator relationships. For HESI success, always set up concentration problems systematically: identify what's changing (active ingredient amount) versus what stays constant (total volume), calculate both original and new concentrations, then apply the percentage change formula carefully. Double-check your arithmetic, as medication calculation errors have serious real-world consequences.

Question 9

The number of patients admitted to a hospital's cardiac unit increased by 150%, from 40 patients last year to the current year's total. How many patients were admitted to the cardiac unit this year?

  1. 60
  2. 100 (correct answer)
  3. 150
  4. 190
Explanation: When you encounter percentage increase problems, remember that the percentage increase is added to the original amount, not replacing it. A 150% increase means the final amount will be the original amount plus 150% of that original amount. Starting with 40 patients last year, you need to calculate what 150% of 40 equals: 40×1.50=6040 \times 1.50 = 60 patients. This represents the increase in admissions. To find this year's total, add this increase to the original number: 40+60=10040 + 60 = 100 patients. You can also solve this in one step by recognizing that a 150% increase means the new total is 250% of the original: 40×2.50=10040 \times 2.50 = 100 patients. Choice A (60) represents a common error—this is only the amount of the increase, not the total number of patients this year. Choice C (150) likely results from confusing the percentage (150%) with the actual number of patients. Choice D (190) might come from incorrectly adding 150 to the original 40, treating the percentage as if it were already a number of patients. For HESI percentage problems, always clarify whether you're looking for the increase amount or the final total. Set up the problem systematically: identify the original value, calculate the increase, then add them together. Double-check by asking yourself if the answer makes logical sense—a 150% increase should more than double the original amount.

Question 10

A patient's resting heart rate increased from 60 beats per minute (bpm) to 75 bpm. Later, it decreased from 75 bpm back to 60 bpm. Which statement accurately compares the percent increase and percent decrease?

  1. The percent increase was equal to the percent decrease.
  2. The percent increase was less than the percent decrease.
  3. The percent increase was greater than the percent decrease. (correct answer)
  4. The percent change cannot be determined without more information.
Explanation: When you encounter percent change problems, remember that the baseline (starting value) matters crucially because it becomes your denominator. Even when the absolute change is identical, different baselines create different percentages. Let's calculate both changes step by step. For the increase from 60 to 75 bpm: the change is 15 bpm, so the percent increase is 1560×100%=25%\frac{15}{60} \times 100\% = 25\%. For the decrease from 75 to 60 bpm: the change is again 15 bpm, but now the percent decrease is 1575×100%=20%\frac{15}{75} \times 100\% = 20\%. The percent increase (25%) was indeed greater than the percent decrease (20%). Option A is incorrect because while the absolute changes were equal (15 bpm each direction), the different baselines (60 vs. 75) create different percentages. Option B reverses the relationship—the increase was actually larger, not smaller, than the decrease. Option D is wrong because we have all the information needed: the starting values and ending values for both changes. This asymmetry in percent changes is why stock market recoveries often take longer than crashes. If a stock drops 50%, it needs to gain more than 50% to return to its original value because the baseline has changed. On the HESI, percent change questions frequently test whether you recognize that equal absolute changes don't create equal percent changes when the baselines differ. Always identify your baseline carefully and remember that percentage calculations depend entirely on what denominator you're using.

Question 11

A pharmaceutical company's stock was valued at $50 per share. It increased by 20% in the first quarter and then decreased by 15% in the second quarter. What was the final value of the stock per share after the second quarter?

  1. $49.50
  2. $51.00 (correct answer)
  3. $52.50
  4. $55.00
Explanation: When you encounter percentage change problems, remember that each percentage change applies to the value at that point in time, not the original value. You must calculate changes sequentially. Start with the initial stock value of $50 per share. In the first quarter, it increased by 20%: $50×1.20=6050 × 1.20 = 60 $ The stock is now worth $60 per share. In the second quarter, it decreased by 15% from this new value of $60: $$60 × 0.85 = 51$$ The final value is $51.00 per share. Choice A ($49.50) represents a common error where students incorrectly subtract 15% from the original $50 value instead of from the 60valueafterthefirstquarterincrease.ChoiceC(60 value after the first quarter increase. Choice C (52.50) likely comes from incorrectly calculating the second quarter as a 10% decrease instead of 15%, or from arithmetic errors in the percentage calculations. Choice D ($55.00) suggests the student only calculated the first quarter increase and forgot to apply the second quarter decrease entirely. The key trap here is forgetting that percentage changes are cumulative - each change builds on the previous result, not the original amount. Always work step-by-step through sequential percentage changes, using your calculated result from each step as the base for the next calculation. This type of compound percentage problem appears frequently on standardized tests, so practice identifying when changes should be applied sequentially versus simultaneously.

Question 12

The number of nursing students at a local college this year is 150, which is an increase of 30 students compared to last year. What was the percentage increase in enrollment from last year to this year?

  1. 20%
  2. 25% (correct answer)
  3. 30%
  4. 80%
Explanation: Percentage increase questions test your ability to calculate how much a quantity has grown relative to its original value. The key is remembering that percentage increase is always calculated using the original (starting) value as your base. To find the percentage increase, you need to determine what the enrollment was last year. Since this year's enrollment of 150 students represents an increase of 30 students, last year's enrollment was 150 - 30 = 120 students. Now you can calculate: Percentage increase=increaseoriginal value×100%=30120×100%=25%\text{Percentage increase} = \frac{\text{increase}}{\text{original value}} \times 100\% = \frac{30}{120} \times 100\% = 25\% Looking at the wrong answers: Choice (A) 20% likely comes from using 150 as the denominator instead of 120 (30/150 = 20%). This is a common error—always use the original value, not the new value, as your base. Choice (C) 30% represents the absolute increase in students, but the question asks for percentage increase, not the raw number. Choice (D) 80% might result from incorrectly calculating 120/150, which would give you the percentage that last year's enrollment represents of this year's enrollment—the opposite of what's asked. When tackling percentage increase problems on the HESI, always identify the original value first, then apply the formula: (increase ÷ original) × 100%. Watch out for the trap of using the final value as your denominator—percentage change is always calculated relative to where you started.

Question 13

A medical supply company offers a 15% discount for orders over $500, followed by an additional 8% discount for paying within 10 days. If a hospital's original order totaled $640, what is the overall percent decrease from the original price after both discounts are applied?

  1. 23.0%
  2. 21.8% (correct answer)
  3. 20.4%
  4. 19.6%
Explanation: First discount (15%): $640 × 0.85 = $544. Second discount (8% of the discounted price): $544 × 0.92 = 500.48.Overallpercentdecrease:(500.48. Overall percent decrease: (640 - $500.48) ÷ $640 × 100 = $139.52 ÷ $640 × 100 = 21.8%. Choice A incorrectly adds the two percentages (15% + 8% = 23%). Choice C represents applying the second discount to the original price rather than the discounted price. Choice D results from calculation errors in the sequential discount application.

Question 14

A patient's daily sodium intake was reduced from 3,000 mg to 2,400 mg. The following week, the intake was reduced again by the same percentage. What was the patient's sodium intake after the second reduction?

  1. 1800 mg
  2. 1820 mg
  3. 1920 mg (correct answer)
  4. 2000 mg
Explanation: When you encounter percentage reduction problems in healthcare calculations, you're working with compound changes where each reduction is based on the new amount, not the original starting point. First, calculate the percentage reduction from the initial change: 3000−24003000=6003000=0.20=20%\frac{3000 - 2400}{3000} = \frac{600}{3000} = 0.20 = 20\% For the second week, apply this same 20% reduction to the current intake of 2,400 mg: 2400×0.20=480 mg reduction2400 \times 0.20 = 480 \text{ mg reduction} Therefore: 2400−480=1920 mg2400 - 480 = 1920 \text{ mg} Answer C (1920 mg) is correct because it properly applies the percentage reduction to the adjusted amount from week one. Answer A (1800 mg) represents a common error where students might calculate 20% of the original 3,000 mg (600 mg) and subtract it twice: 3000 - 600 - 600 = 1800. This incorrectly treats both reductions as if they're based on the original amount. Answer B (1820 mg) likely results from calculation errors or incorrect percentage applications during the multi-step process. Answer D (2000 mg) might occur if you mistakenly subtract a flat 400 mg (the difference between 2400 and 2000) instead of calculating the proper percentage reduction. Study tip: In compound percentage problems, always apply each percentage change to the most recent value, not the original starting point. This pattern appears frequently in medication dosing and dietary modification questions on the HESI.

Question 15

A medication's effectiveness rate increased from 72% to 81% after reformulation. A competing medication's effectiveness increased from 65% to 78%. Which medication had the greater percent increase in effectiveness, and by how much?

  1. The competing medication by 7.5 percentage points
  2. The competing medication by 7.5 percent (correct answer)
  3. The first medication by 2.0 percent
  4. Both medications had equal percent increases
Explanation: First medication: percent increase = (81 - 72) ÷ 72 × 100 = 12.5%. Competing medication: percent increase = (78 - 65) ÷ 65 × 100 = 20.0%. The competing medication had a greater percent increase by 20.0% - 12.5% = 7.5 percent. Choice A confuses percentage points with percent increase. Choice C incorrectly calculates which medication had the greater increase. Choice D fails to recognize the different bases for calculation (72 vs 65).

Question 16

A pharmacy's inventory management system shows that after a 20% price increase, a medication's sales volume decreased such that total revenue remained unchanged. What was the percent decrease in sales volume?

  1. 25.00% decrease in volume
  2. 20.00% decrease in volume
  3. 16.67% decrease in volume (correct answer)
  4. 33.33% decrease in volume
Explanation: When you encounter questions about price changes and sales volume where total revenue remains constant, you're working with inverse proportional relationships. The key insight is that if price goes up and revenue stays the same, volume must decrease proportionally. Let's set up the relationship mathematically. If original price is P and original volume is V, then original revenue = P × V. After changes: new revenue = (1.20P) × (new volume) = P × V. Solving for the new volume: (1.20P) × (new volume) = P × V, so new volume = V ÷ 1.20 = V ÷ (6/5) = V × (5/6) = 0.8333V. This means the new volume is 83.33% of the original volume, representing a decrease of 100% - 83.33% = 16.67%. Looking at the wrong answers: Choice A (25% decrease) represents a common error where students incorrectly assume that a 20% price increase requires a 25% volume decrease (since 1 ÷ 1.20 ≈ 0.80). Choice B (20% decrease) is the trap of assuming the percentage changes are equal, which would actually increase total revenue. Choice D (33.33% decrease) comes from confusing the relationship direction or making calculation errors. For HESI pharmacy calculations, remember that when price and volume changes result in constant revenue, use the formula: percent volume change = (1 ÷ price multiplier - 1) × 100%. This inverse relationship pattern appears frequently in healthcare economics questions.

Question 17

A nurse's hourly wage increased from $28.50 to $32.20. If she works 36 hours per week, what is her percent increase in weekly earnings, and how much additional money does she earn per week?

  1. 13.68% increase, $140.00 additional weekly
  2. 13.00% increase, $135.00 additional weekly
  3. 12.98% increase, $133.20 additional weekly (correct answer)
  4. 15.00% increase, $153.60 additional weekly
Explanation: Percentage increase problems on the HESI often test your ability to calculate both the percent change and the absolute dollar difference. When you see wage increase questions, you need to find the new weekly earnings, compare them to the old weekly earnings, then calculate the percentage change. First, calculate the weekly earnings before and after the raise. Original weekly earnings: 28.50×36=$1,02628.50 × 36 = \$1,026. New weekly earnings: 32.20×36=$1,159.2032.20 × 36 = \$1,159.20. The additional weekly earnings are: 1,159.20−1,026=$133.201,159.20 - 1,026 = \$133.20. To find the percent increase, use the formula: new value - old valueold value×100%\frac{\text{new value - old value}}{\text{old value}} × 100\%. This gives us: 133.201,026×100%=12.98%\frac{133.20}{1,026} × 100\% = 12.98\%. Option A calculates 13.68% increase with $140 additional weekly earnings - this appears to use incorrect hourly calculations or rounding errors. Option B shows 13% with $135 additional - this likely rounds the percentage too early in the calculation, leading to compounding errors in the dollar amount. Option D gives 15% with $153.60 additional - this significantly overestimates both values, possibly from calculation errors in the basic multiplication steps. Option C correctly shows 12.98% increase and $133.20 additional weekly earnings, matching our precise calculations. For HESI math problems involving wages and percentages, always calculate the exact dollar amounts first, then use those precise figures for your percentage calculations. Avoid premature rounding, as it can lead you to attractive but incorrect answer choices.

Question 18

A physical therapy clinic's patient volume changed as follows over three consecutive months: increased 25% in month 1, decreased 20% in month 2, and increased 10% in month 3. If they ended with 330 patients, how many patients did they have initially?

  1. 250 patients initially
  2. 280 patients initially
  3. 275 patients initially
  4. 300 patients initially (correct answer)
Explanation: When you encounter sequential percentage changes in healthcare administration problems, you need to work backwards from the final value to find the initial amount. Each percentage change creates a multiplier that you apply to track the patient volume through time. Let's call the initial number of patients xx and trace through each month. In month 1, a 25% increase means the volume becomes 1.25x1.25x. In month 2, a 20% decrease from that new level gives us 1.25x×0.80=1.00x1.25x \times 0.80 = 1.00x. Finally, month 3's 10% increase results in 1.00x×1.10=1.10x=3301.00x \times 1.10 = 1.10x = 330 patients. Solving for xx: x=3301.10=300x = \frac{330}{1.10} = 300 patients initially. Choice A (250 patients) represents a common error where students might incorrectly calculate the net percentage change as +25% - 20% + 10% = +15%, then work backwards using 250 × 1.15 ≈ 288, which doesn't match the final value. Choice B (280 patients) likely results from arithmetic errors in the sequential calculations or confusion about which direction to apply the percentages. Choice C (275 patients) appears to stem from incorrectly handling the compounding effect of percentage changes, possibly by averaging values inappropriately. For percentage change problems on the HESI, always remember that each change builds on the previous result, not the original value. Set up your equation by multiplying all the change factors together, then work backwards from the final value to avoid calculation errors.

Question 19

A patient's weight decreased from 180 pounds to 162 pounds over three months. What was the percentage decrease in the patient's weight?

  1. 9%
  2. 10% (correct answer)
  3. 11.1%
  4. 18%
Explanation: When you encounter percentage change problems on the HESI, you're applying a fundamental formula that appears frequently in healthcare calculations, from medication dosages to patient monitoring metrics. To find percentage decrease, use this formula: Percentage decrease=Original value−New valueOriginal value×100\text{Percentage decrease} = \frac{\text{Original value} - \text{New value}}{\text{Original value}} \times 100 Here, the patient's original weight was 180 pounds and the new weight is 162 pounds. First, calculate the actual decrease: 180 - 162 = 18 pounds. Then divide this decrease by the original weight: 18180=0.10\frac{18}{180} = 0.10. Finally, convert to percentage: 0.10 × 100 = 10%. Looking at the incorrect options: Choice (A) 9% represents a calculation error, likely from rounding too early or miscalculating the fraction. Choice (C) 11.1% occurs when students accidentally use the new weight (162) as the denominator instead of the original weight (180) - this gives you 18/162 ≈ 0.111. Choice (D) 18% is the trap answer where students report the absolute weight loss (18 pounds) as if it were already a percentage. The correct answer is (B) 10%. Study tip: Always use the original value as your denominator in percentage change calculations. A quick check: if someone loses 18 pounds from 180 pounds, that's roughly 1/10 of their body weight, which should immediately suggest 10%. This mental approximation can help you catch calculation errors on exam day.

Question 20

An IV drip rate is increased by 20% to a new rate of 120 mL/hr. What was the original drip rate?

  1. 96 mL/hr
  2. 100 mL/hr (correct answer)
  3. 108 mL/hr
  4. 144 mL/hr
Explanation: When you encounter percentage increase problems in healthcare calculations, you're working backwards from the final result to find the original value. This type of problem tests your ability to set up and solve equations involving percentages. Let's call the original drip rate xx. If the rate increased by 20%, the new rate equals the original rate plus 20% of the original rate. This gives us the equation: x+0.20x=120x + 0.20x = 120. Combining like terms: 1.20x=1201.20x = 120. Solving for xx: x=120÷1.20=100x = 120 ÷ 1.20 = 100 mL/hr. You can verify this: if the original rate was 100 mL/hr, a 20% increase would be 100×0.20=20100 × 0.20 = 20 mL/hr, making the new rate 100+20=120100 + 20 = 120 mL/hr. ✓ Now let's examine why the other options are incorrect. Choice A (96 mL/hr) represents a common error where students subtract 20% from 120 instead of working backwards (120×0.80=96120 × 0.80 = 96). Choice C (108 mL/hr) might result from incorrectly calculating 120−12120 - 12 after finding 10% of 120. Choice D (144 mL/hr) comes from mistakenly adding 20% to 120 instead of recognizing that 120 is already the increased amount. Remember this key strategy: when a value has already been increased by a percentage, divide by (1+percentage as decimal)(1 + \text{percentage as decimal}) to find the original. For decreases, divide by (1−percentage as decimal)(1 - \text{percentage as decimal}). This backward-calculation skill is essential for medication dosing problems on the HESI.