Health Education Systems Inc (HESI) A2 Exam Quiz: Measurement Problems

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Measurement ProblemsQuestion 1 of 20

A catheter has a diameter of 5/16 of an inch. What is this diameter in millimeters, rounded to the nearest whole number? (Use 1 inch = 2.54 cm)

1 mm

4 mm

8 mm

13 mm

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Health Education Systems Inc (HESI) A2 Exam Quiz

Health Education Systems Inc (HESI) A2 Exam Quiz: Measurement Problems

Practice Measurement Problems 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 Measurement Problems, giving you a quick way to practice the rules, question types, and explanations that matter most for Health Education Systems Inc (HESI) A2 Exam.

How to use this quiz

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.

All questions

Question 1

A catheter has a diameter of 5/16 of an inch. What is this diameter in millimeters, rounded to the nearest whole number? (Use 1 inch = 2.54 cm)

1 mm
4 mm
8 mm (correct answer)
13 mm

Explanation: When you encounter unit conversion problems on the HESI, you need to work systematically through multiple conversion steps, keeping track of your units to avoid calculation errors. To convert 5/16 inch to millimeters, you'll use the given conversion factor and convert through centimeters. First, convert the fraction to decimal form:

\frac{5}{16} = 0.3125

inches. Next, convert inches to centimeters:

0.3125 \text{ inches} \times 2.54 \frac{\text{cm}}{\text{inch}} = 0.79375 \text{ cm}

Finally, convert centimeters to millimeters (since 1 cm = 10 mm):

0.79375 \text{ cm} \times 10 \frac{\text{mm}}{\text{cm}} = 7.9375 \text{ mm}

Rounded to the nearest whole number, this gives us 8 mm, making C correct. Let's examine why the other answers miss the mark: A) 1 mm results from a major calculation error, likely forgetting to multiply by 10 when converting from centimeters to millimeters. B) 4 mm suggests you may have converted incorrectly or rounded prematurely during intermediate steps. D) 13 mm indicates a significant miscalculation, possibly multiplying instead of converting properly or using an incorrect conversion factor. For HESI math problems, always write out each conversion step clearly and keep your units labeled throughout. Don't try to do multiple conversions in your head—work methodically from the given units to the target units, and double-check that your final answer makes logical sense given the original measurement.

Question 2

A wound measures 4.5 inches in length. A nurse needs to document this length in millimeters. What is the length of the wound in mm? (Use 1 inch = 2.54 cm)

11.4 mm
17.7 mm
114.3 mm (correct answer)
177.2 mm

Explanation: When you encounter unit conversion problems on the HESI, you need to work systematically through multiple steps to avoid calculation errors that lead to wrong answer choices. To convert 4.5 inches to millimeters, you'll use the given conversion factor (1 inch = 2.54 cm) plus the metric relationship between centimeters and millimeters (1 cm = 10 mm). First, convert inches to centimeters:

4.5 \text{ inches} \times 2.54 \frac{\text{cm}}{\text{inch}} = 11.43 \text{ cm}

Next, convert centimeters to millimeters:

11.43 \text{ cm} \times 10 \frac{\text{mm}}{\text{cm}} = 114.3 \text{ mm}

This confirms answer C (114.3 mm) is correct. Looking at the wrong answers: A (11.4 mm) represents stopping after the first conversion step—you calculated centimeters but forgot to convert to millimeters. B (17.7 mm) likely results from incorrectly dividing 4.5 by 2.54 instead of multiplying, then converting to millimeters. D (177.2 mm) suggests using an incorrect conversion factor, possibly confusing the 2.54 relationship or making an arithmetic error in the final step. Each distractor represents a common mistake in multi-step conversions: forgetting a conversion step, using the wrong mathematical operation, or applying incorrect conversion factors. Study tip: For HESI unit conversions, always write out each step clearly and double-check that your final units match what the question asks for. Practice converting between metric units (especially cm to mm) since these appear frequently in healthcare calculations.

Question 3

A patient is prescribed a liquid medication to be taken as 15 mL three times a day. How many liters of the medication will the patient consume in a 30-day period?

0.45 L
1.35 L (correct answer)
1.50 L
13.5 L

Explanation: Dosage calculation questions on the HESI require you to systematically convert units and track time periods. When you see questions involving daily medication doses over extended periods, break the problem into clear steps to avoid calculation errors. Let's work through this step-by-step. The patient takes 15 mL three times daily, so the daily consumption is:

15 \text{ mL} \times 3 = 45 \text{ mL per day}

Over 30 days, the total volume consumed is:

45 \text{ mL/day} \times 30 \text{ days} = 1,350 \text{ mL}

Since the answer choices are in liters, convert milliliters to liters by dividing by 1,000:

1,350 \text{ mL} \div 1,000 = 1.35 \text{ L}

Now let's examine why the other answers are incorrect. Choice A (0.45 L) represents only 10 days of medication instead of 30 days—this suggests calculating

15 \times 3 \times 10 \div 1,000

. Choice C (1.50 L) likely comes from incorrectly calculating 15 mL twice daily instead of three times daily over 30 days. Choice D (13.5 L) results from forgetting to convert from milliliters to liters, leaving the answer as 1,350 but changing the units to liters. For HESI dosage calculations, always write out each step clearly: identify the dose per administration, multiply by frequency per day, multiply by total days, then convert units as needed. Double-check your unit conversions—many students lose points by getting the math right but forgetting that 1,000 mL equals 1 L.

Question 4

A pharmacist is preparing a cream by mixing 0.08 kg of an active ingredient powder with 1.5 lbs of a base cream. What is the approximate total weight of the final mixture in grams? (Use 1 lb ≈ 454 g)

534 g
681 g
761 g (correct answer)
830 g

Explanation: When you encounter medication preparation problems involving mixed units, your first step is always to convert everything to the same unit system before calculating totals. You have two components to convert and add:

Active ingredient: 0.08 kg
Base cream: 1.5 lbs

Converting the active ingredient:

0.08 \text{ kg} \times 1000 \text{ g/kg} = 80 \text{ g}

Converting the base cream:

1.5 \text{ lbs} \times 454 \text{ g/lb} = 681 \text{ g}

Total mixture weight:

80 \text{ g} + 681 \text{ g} = 761 \text{ g}

Looking at the wrong answers: Choice A (534 g) likely results from incorrectly converting kilograms (perhaps using 454 instead of 1000 as the conversion factor). Choice B (681 g) is the weight of just the base cream alone—this happens when students forget to add the active ingredient. Choice D (830 g) suggests a calculation error, possibly from rounding the pound conversion incorrectly or making an arithmetic mistake in the final addition. For pharmacy calculations on the HESI, always write down your unit conversions explicitly and double-check that you've included all components in your final answer. The most common errors are forgetting to convert units properly and leaving out one of the ingredients in mixed preparation problems.

Question 5

A dosage of 3 mg per kg of body weight is ordered for a child who weighs 66 lbs. How many milligrams of the medication should be administered? (Use 1 kg = 2.2 lbs)

30 mg
90 mg (correct answer)
198 mg
436 mg

Explanation: Pediatric dosage calculations require converting between weight units and applying dosing formulas accurately. When you encounter weight-based dosing problems, always convert to the same units first, then calculate the total dose. Start by converting the child's weight from pounds to kilograms:

\frac{66 \text{ lbs}}{2.2 \text{ lbs/kg}} = 30 \text{ kg}

. Now multiply the weight by the ordered dose:

30 \text{ kg} \times 3 \text{ mg/kg} = 90 \text{ mg}

. This gives you the total milligrams to administer. Looking at the wrong answers: Choice A (30 mg) represents a common error where students use the converted weight in kilograms as the final answer, forgetting to multiply by the dosage per kilogram. Choice C (198 mg) occurs when students multiply the original weight in pounds (66) by the dosage (3), skipping the conversion to kilograms entirely. Choice D (436 mg) happens when students incorrectly multiply 66 pounds by 2.2 and then by 3, essentially double-converting the weight. For HESI dosage calculations, always follow this three-step approach: first convert all measurements to matching units, then apply the dosing formula systematically, and finally double-check that your answer makes clinical sense. Remember that pediatric doses are typically much smaller than adult doses, so extremely high numbers should raise red flags. Practice unit conversions until they become automatic—this foundational skill will serve you well across many medication calculation scenarios.

Question 6

A standard roll of medical tape is 10 yards long. If a nurse uses 65 cm of tape for each of 12 patients, how many meters of tape are left on the roll? (Use 1 yard = 0.914 m)

1.34 m (correct answer)
7.80 m
8.49 m
9.14 m

Explanation: Unit conversion problems in healthcare require systematic thinking about dimensional analysis. When you encounter a multi-step conversion problem, always identify what units you're starting with, what units you need to end with, and map out each conversion step before calculating. Start by converting the total tape length from yards to meters:

10 \text{ yards} \times 0.914 \frac{\text{m}}{\text{yard}} = 9.14 \text{ m}

Next, calculate the total tape used. Convert centimeters to meters first:

65 \text{ cm} = 0.65 \text{ m per patient}

For 12 patients:

0.65 \text{ m/patient} \times 12 \text{ patients} = 7.8 \text{ m used}

Finally, subtract to find remaining tape:

9.14 \text{ m} - 7.8 \text{ m} = 1.34 \text{ m}

Answer A (1.34 m) is correct. Answer B (7.80 m) represents the amount of tape used, not what's left—a common trap when students calculate correctly but answer the wrong question. Answer C (8.49 m) likely results from incorrectly adding instead of subtracting the used tape from the total. Answer D (9.14 m) is the original length of the roll before any tape was used, suggesting the student forgot to account for the tape consumption entirely. For HESI math problems, always double-check that your final answer makes logical sense and that you're answering what the question actually asks. Converting everything to the same units early prevents errors and makes calculations cleaner.

Question 7

A rectangular hospital room measures 4.2 meters by 5.8 meters. The flooring costs $32.50 per square meter, and an additional 8% of the calculated area must be ordered to account for waste. What is the total cost of flooring for this room?

$855.08 is the total cost of flooring for the room (correct answer)
$792.70 is the total cost of flooring for the room
$967.23 is the total cost of flooring for the room
$1,012.58 is the total cost of flooring for the room

Explanation: Room area = 4.2 × 5.8 = 24.36 m². Area including waste = 24.36 × 1.08 = 26.31 m². Total cost = 26.31 × $32.50 = $855.08. Choice B uses the base area without waste allowance (24.36 × $32.50 = $792.70). Choice C incorrectly adds 15% waste instead of 8%. Choice D uses an incorrect area calculation.

Question 8

A patient weighs 165 pounds and needs a medication dosed at 12 mg per kilogram of body weight. The medication is available in a suspension containing 40 mg per 5 mL. How many milliliters should the nurse administer?

112.5 mL should be administered to the patient (correct answer)
125.3 mL should be administered to the patient
134.7 mL should be administered to the patient
148.9 mL should be administered to the patient

Explanation: Convert weight: 165 lb ÷ 2.2 lb/kg = 75 kg. Calculate dose: 75 kg × 12 mg/kg = 900 mg needed. Suspension concentration: 40 mg per 5 mL = 8 mg/mL. Volume needed: 900 mg ÷ 8 mg/mL = 112.5 mL. Choice B uses an incorrect weight conversion factor. Choice C miscalculates the suspension concentration. Choice D uses pounds instead of kilograms in the dose calculation.

Question 9

A patient's height is recorded as 5 feet 10 inches. To calculate their Body Mass Index (BMI), the nurse must convert this height to meters. What is the patient's height in meters? (Use 1 inch = 2.54 cm)

1.52 m
1.78 m (correct answer)
2.08 m
2.54 m

Explanation: Unit conversion questions are fundamental in healthcare because accurate measurements are critical for patient safety, especially when calculating BMI, medication dosages, and other clinical values. When converting height from feet and inches to meters, you need to work systematically through the conversion process. To solve this problem, first convert the total height to inches: 5 feet × 12 inches/foot = 60 inches, plus 10 inches = 70 inches total. Next, convert inches to centimeters using the given conversion factor: 70 inches × 2.54 cm/inch = 177.8 cm. Finally, convert centimeters to meters by dividing by 100: 177.8 cm ÷ 100 = 1.778 m, which rounds to 1.78 m. Looking at the incorrect options: Choice A (1.52 m) represents a calculation error, possibly from converting only the 5 feet portion or making an arithmetic mistake in the multiplication. Choice C (2.08 m) suggests an error in the conversion process, perhaps adding instead of properly converting units. Choice D (2.54 m) indicates confusion between the conversion factor itself (2.54 cm/inch) and the final answer. The correct answer is B) 1.78 m. Study tip: For HESI unit conversion problems, always write out each step clearly: original units → intermediate units → final units. Double-check that your final answer makes sense – a height of 1.78 m (about 5'10") is reasonable for an adult, while 2.54 m would be over 8 feet tall. Practice the common conversions used in healthcare settings.

Question 10

A physical therapist instructs a patient to walk 2.5 kilometers. The indoor track is 200 yards long. Approximately how many full laps must the patient complete to meet this goal? (Use 1 mile = 1.6 km and 1 mile = 1760 yards)

12 laps
14 laps (correct answer)
22 laps
28 laps

Explanation: Unit conversion problems like this are common on healthcare exams because you'll need to convert between measurement systems in clinical practice. The key is working systematically through the conversions and avoiding calculation errors. Start by converting the target distance from kilometers to yards using the given conversion factors. You need to walk 2.5 km, and you know that 1 mile = 1.6 km and 1 mile = 1760 yards. First, convert kilometers to miles:

2.5 \text{ km} \times \frac{1 \text{ mile}}{1.6 \text{ km}} = 1.5625 \text{ miles}

Next, convert miles to yards:

1.5625 \text{ miles} \times \frac{1760 \text{ yards}}{1 \text{ mile}} = 2750 \text{ yards}

Finally, divide by the track length to find the number of laps:

\frac{2750 \text{ yards}}{200 \text{ yards per lap}} = 13.75 \text{ laps}

Since you need full laps, round up to 14 laps, making B correct. Looking at the wrong answers: A (12 laps) represents rounding down instead of up, which wouldn't meet the full distance requirement. C (22 laps) likely results from using incorrect conversion factors or making arithmetic errors in the calculation process. D (28 laps) suggests a major calculation error, possibly doubling the correct answer or confusing conversion factors. For conversion problems, always write out your work step-by-step and double-check your arithmetic. Remember that healthcare often requires rounding up to ensure patients receive adequate treatment or meet minimum requirements.

Question 11

A patient on a fluid restriction of 1.5 liters per day has consumed a 6 oz cup of tea and 300 mL of water. How many milliliters of fluid can the patient consume for the remainder of the day? (Use 1 oz ≈ 30 mL)

480 mL
1020 mL (correct answer)
1194 mL
1200 mL

Explanation: Fluid restriction calculations are common in nursing practice and require careful unit conversions and addition. When you encounter these problems, always convert everything to the same units first, then work with the totals. Let's solve this step by step. The patient has a daily fluid restriction of 1.5 liters, which equals 1,500 mL. Now we need to calculate what they've already consumed:

Tea: 6 oz × 30 mL/oz = 180 mL
Water: 300 mL (already in correct units)
Total consumed: 180 mL + 300 mL = 480 mL

To find remaining allowance: 1,500 mL - 480 mL = 1,020 mL Looking at the answer choices, option B (1020 mL) correctly represents this calculation. Option A (480 mL) is a trap - this represents only what the patient has already consumed, not what remains available. Option C (1194 mL) likely results from an incorrect conversion error, perhaps using 29 mL/oz instead of 30 mL/oz. Option D (1200 mL) might come from forgetting to subtract the tea consumption and only accounting for the water. For HESI fluid calculation questions, always follow this systematic approach: convert all volumes to the same unit (usually mL), add up what's been consumed, then subtract from the total allowance. Double-check your unit conversions - the standard 1 oz ≈ 30 mL conversion appears frequently on nursing exams.

Question 12

An infant weighs 3.4 kg at birth. In the first week, the infant loses 10% of their birth weight. Over the next 5 days, the infant gains 120 g per day. What is the infant's weight in kilograms at the end of this period?

3.18 kg
3.66 kg (correct answer)
3.74 kg
4.00 kg

Explanation: Weight change problems in healthcare require careful step-by-step calculation, especially when tracking infant weight loss and gain patterns. You'll need to calculate each change sequentially from the starting point. Start with the birth weight of 3.4 kg. In the first week, the infant loses 10% of birth weight:

3.4 \times 0.10 = 0.34 \text{ kg}

. So after one week, the weight is

3.4 - 0.34 = 3.06 \text{ kg}

. Next, over 5 days, the infant gains 120 g per day. Total weight gain is

120 \times 5 = 600 \text{ g} = 0.6 \text{ kg}

. Adding this to the week-one weight:

3.06 + 0.6 = 3.66 \text{ kg}

. Looking at the wrong answers: Choice A (3.18 kg) represents the weight if you only calculated the initial loss but forgot about the subsequent gains. Choice C (3.74 kg) likely comes from miscalculating the percentage loss as 8% instead of 10%, then adding the gains correctly. Choice D (4.00 kg) suggests adding the total gains to birth weight without accounting for the initial loss. The correct answer is B) 3.66 kg. For HESI math problems involving sequential changes, always work through each step chronologically and double-check your unit conversions between grams and kilograms. Write down each calculation step to avoid mixing up the sequence—this prevents the common error of applying changes to the wrong starting weight.

Question 13

A nurse must apply a dressing to three separate wounds. Each wound requires a strip of dressing 5 inches long. What is the total length of dressing material needed in centimeters? (Use 1 inch = 2.54 cm)

12.70 cm
25.40 cm
38.10 cm (correct answer)
45.72 cm

Explanation: Unit conversion questions on the HESI exam test your ability to perform multi-step calculations accurately while working with different measurement systems. When you encounter problems involving both multiplication and conversion, break them into clear steps to avoid calculation errors. First, calculate the total length needed in inches. Since you have three wounds requiring 5 inches each:

3 \times 5 = 15

inches total. Next, convert inches to centimeters using the given conversion factor. With 1 inch = 2.54 cm:

15 \times 2.54 = 38.10

cm. Let's examine why the other options are incorrect. Option A (12.70 cm) represents a common error where students convert only one strip length instead of the total:

5 \times 2.54 = 12.70

cm. This ignores that three strips are needed. Option B (25.40 cm) occurs when students convert 10 inches instead of 15, perhaps miscounting the strips or making an arithmetic error:

10 \times 2.54 = 25.40

cm. Option D (45.72 cm) suggests converting 18 inches instead of 15:

18 \times 2.54 = 45.72

cm, indicating a multiplication mistake in the first step. The correct answer is C (38.10 cm). For HESI math questions involving multiple steps, always write out each calculation clearly and double-check your arithmetic before converting units. Many students rush through the multiplication step, so take extra care with basic math operations even when the conversion factor seems like the challenging part.

Question 14

A patient is given a 1-pint bottle of a nutritional supplement and is instructed to drink half of it. The patient drinks 200 mL. How many milliliters more or less than the instructed amount did the patient drink? (Use 1 pint ≈ 473 mL)

36.5 mL less (correct answer)
36.5 mL more
73.0 mL less
73.0 mL more

Explanation: When you encounter dosage calculation problems involving unit conversions, always start by converting everything to the same units, then calculate the intended dose before comparing to what was actually taken. First, convert the 1-pint bottle to milliliters:

1 \text{ pint} \times 473 \text{ mL/pint} = 473 \text{ mL}

. The patient was instructed to drink half of this amount:

473 \text{ mL} ÷ 2 = 236.5 \text{ mL}

. The patient actually drank 200 mL, so the difference is:

236.5 \text{ mL} - 200 \text{ mL} = 36.5 \text{ mL}

. Since the patient drank less than instructed, the answer is 36.5 mL less. Looking at the wrong answers: Choice B (36.5 mL more) gets the calculation right but reverses the direction—the patient drank less, not more, than instructed. Choice C (73.0 mL less) likely comes from incorrectly calculating the difference as

273 \text{ mL} - 200 \text{ mL}

instead of using the correct half-bottle amount of 236.5 mL. Choice D (73.0 mL more) combines both errors—using the wrong baseline calculation and the wrong direction. For HESI dosage problems, always work systematically: convert units first, calculate the target amount, find the actual difference, then determine whether it's more or less than intended. Pay special attention to the wording—"more or less than" questions require you to determine both the magnitude and direction of the difference.

Question 15

A lab technician needs to measure 0.35 liters of a reagent, but only has a graduated cylinder marked in milliliters. The technician accidentally measures 305 mL. What is the measurement error in cubic centimeters (cc)?

45 cc (correct answer)
55 cc
305 cc
655 cc

Explanation: This question tests your ability to work with measurement conversions and calculate error - both essential skills in healthcare settings where precision matters for patient safety. To find the measurement error, you need to determine the difference between what should have been measured and what was actually measured. First, convert the target amount to milliliters: 0.35 liters × 1000 mL/L = 350 mL. The technician measured 305 mL instead of 350 mL, creating an error of 350 - 305 = 45 mL. Since 1 mL = 1 cc, the error is 45 cc. Looking at the wrong answers: Choice B (55 cc) likely comes from incorrectly subtracting 305 - 350 and taking the absolute value, or from a conversion error. Choice C (305 cc) represents the actual measurement taken, not the error - this confuses the measured value with the deviation from the target. Choice D (655 cc) appears to come from adding the target and measured amounts (350 + 305), which has no relevance to calculating error. When solving measurement error problems on the HESI, always follow this three-step process: convert all units to match, find the difference between target and actual values, then convert to the requested units if needed. Remember that "error" means the deviation from the intended value, not the measurement itself. Practice these conversions since healthcare professionals must be precise with dosage calculations and laboratory measurements.

Question 16

A patient's IV bag contains 1000 mL of fluid and is infusing at a rate of 125 mL per hour. After 4.5 hours, the nurse discovers that an additional 75 mL has leaked from a loose connection. What is the total volume of fluid the patient actually received?

487.5 mL of fluid was received by the patient (correct answer)
512.5 mL of fluid was received by the patient
562.5 mL of fluid was received by the patient
637.5 mL of fluid was received by the patient

Explanation: Total fluid that should have infused: 125 mL/hr × 4.5 hr = 562.5 mL. However, 75 mL leaked and did not reach the patient. Therefore, actual fluid received = 562.5 - 75 = 487.5 mL. Choice B incorrectly adds half the leaked amount. Choice C represents the total calculated infusion without subtracting the leaked amount. Choice D incorrectly adds the leaked volume to the calculated infusion.

Question 17

A pharmacist mixes 350 mL of solution A, 0.6 L of solution B, and 400 cc of solution C. The final mixture is divided equally into 5 containers. How many milliliters are in each container?

147 mL
270 mL (correct answer)
350 mL
1350 mL

Explanation: When you encounter dosage calculation problems involving multiple solutions and containers, you need to work systematically through unit conversions, total volume calculation, and final division. First, convert all volumes to the same unit (milliliters): Solution A is 350 mL, solution B is 0.6 L = 600 mL (since 1 L = 1000 mL), and solution C is 400 cc = 400 mL (since 1 cc = 1 mL). The total volume is

350 + 600 + 400 = 1350

mL. Since this total is divided equally into 5 containers, each container holds

1350 ÷ 5 = 270

mL, making B the correct answer. Looking at the wrong answers: A) 147 mL likely results from calculation errors in either the conversion step or division. C) 350 mL represents only the volume of solution A, suggesting you might have forgotten to include solutions B and C in your total. D) 1350 mL is the total volume before division—a common error where students calculate the combined volume correctly but forget the final step of dividing into containers. For HESI dosage calculations, always establish a systematic approach: convert all measurements to the same units first, perform your arithmetic carefully, and double-check that you've answered what the question actually asks. Many students get tripped up by stopping one step early or mixing up units, so take time to verify your conversions and ensure your final answer matches the question's requirements.

Question 18

Patient A weighs 187 lbs. Patient B weighs 81 kg. What is the approximate weight difference between them in kilograms? (Use 1 kg = 2.2 lbs)

4 kg (correct answer)
106 kg
126 kg
330 kg

Explanation: Unit conversion problems are fundamental in healthcare, where you'll frequently need to convert between different measurement systems for medications, patient weights, and other clinical calculations. To solve this problem, you need to convert both weights to the same unit (kilograms) and find the difference. Patient A weighs 187 lbs, which converts to:

187 \div 2.2 = 85 \text{ kg}

. Patient B already weighs 81 kg. The difference is:

85 - 81 = 4 \text{ kg}

. Looking at the answer choices, option A (4 kg) is correct. Option B (106 kg) represents a common error where students might add the original pound weight to the kilogram weight (187 - 81 = 106), forgetting to convert units first. Option C (126 kg) could result from incorrectly multiplying instead of dividing during conversion, then subtracting (187 × 2.2 = 411.4 kg, with some subsequent calculation error). Option D (330 kg) appears to come from adding rather than subtracting the converted weights (85 + 81 = 166, though the exact path to 330 isn't clear). For HESI math problems involving conversions, always convert everything to the same unit before performing calculations. Write out your conversion factors clearly: to go from pounds to kilograms, divide by 2.2. Double-check that your final answer makes logical sense—a 4 kg difference between two adult patients is reasonable, while differences over 100 kg would be extreme.

Question 19

A patient's meal tray includes a piece of chicken weighing 150 g and a serving of vegetables weighing 1.2 oz. What is the total weight of these two items in grams? (Use 1 oz ≈ 28 g)

151.2 g
178.0 g
183.6 g (correct answer)
204.0 g

Explanation: Unit conversion problems on the HESI frequently test your ability to work with different measurement systems, particularly when calculating medication dosages or nutritional information. The key is identifying what units you're given and systematically converting everything to the target unit. You have two food items with different units: chicken at 150 g and vegetables at 1.2 oz. Since the question asks for the total weight in grams, you need to convert the vegetables from ounces to grams, then add both weights. Using the given conversion factor:

1.2 \text{ oz} \times 28 \frac{\text{g}}{\text{oz}} = 33.6 \text{ g}

Total weight = 150 g (chicken) + 33.6 g (vegetables) = 183.6 g Looking at the wrong answers: A) 151.2 g incorrectly adds 1.2 directly to 150, forgetting to convert ounces to grams entirely. B) 178.0 g likely results from using an incorrect conversion factor or rounding error during calculation. D) 204.0 g suggests a calculation error, possibly multiplying instead of converting properly or using the wrong conversion factor. For HESI success with unit conversions, always write out your conversion factor as a fraction to ensure units cancel properly. Double-check that you're converting to the correct target unit before doing any addition or subtraction. Many students rush through these problems and forget the conversion step entirely, which is exactly what answer choice A represents.

Question 20

A 2-liter IV bag of saline is administered to a patient at a rate of 150 mL per hour. After 5 hours, how many cups of saline remain in the bag? (Use 1 cup ≈ 240 mL)

3.1 cups
5.2 cups (correct answer)
7.7 cups
8.3 cups

Explanation: IV fluid calculation problems test your ability to track fluid administration over time and convert between different units of measurement. When you encounter these questions, break them down into clear steps: calculate what's been used, determine what remains, then convert to the requested units. Start by finding how much saline was administered over 5 hours:

150 \text{ mL/hour} \times 5 \text{ hours} = 750 \text{ mL}

. The original bag contained 2 liters, which equals 2,000 mL. Subtract the amount given:

2,000 \text{ mL} - 750 \text{ mL} = 1,250 \text{ mL}

remaining. Finally, convert to cups using the given conversion factor:

\frac{1,250 \text{ mL}}{240 \text{ mL/cup}} = 5.2 \text{ cups}

. This matches answer choice B. Let's examine why the other options are incorrect. Choice A (3.1 cups) represents approximately 744 mL, which is close to the amount already administered rather than what remains. Choice C (7.7 cups) equals about 1,848 mL, suggesting you might have subtracted incorrectly or confused the calculation steps. Choice D (8.3 cups) represents nearly the entire original volume without accounting for any fluid administration. For HESI math problems involving IV calculations, always work systematically: identify starting amounts, calculate changes over time, then convert units at the end. Double-check your unit conversions since these are common error points, and ensure you're answering what the question actually asks for—remaining volume, not administered volume.