All questions
Question 1
Town A has a population of 12,000 and is growing by 250 people per year. Town B has a population of 15,000 and is decreasing by 150 people per year. Which equation can be used to find y, the number of years it will take for the two towns to have the same population?
- 12000 + 250y = 15000 - 150y (correct answer)
- 12000 + 250y = 15000 + 150y
- 250y - 150y = 15000 + 12000
- 12000 - 250y = 15000 + 150y
Explanation: The population of Town A after y years will be its initial population plus the growth: 12000 + 250y. The population of Town B after y years will be its initial population minus the decrease: 15000 - 150y. To find when the populations are equal, we set these two expressions equal to each other: 12000 + 250y = 15000 - 150y.
Question 2
A rectangular garden has a perimeter of 120 feet. The length of the garden is twice its width. Which equation represents the perimeter of the garden in terms of its width, w?
- w(2w) = 120
- w + 2w = 120
- 2w + 2(2w) = 120 (correct answer)
- 2(w + 2w) = 60
Explanation: Let the width be w. The length is twice the width, so L = 2w. The formula for the perimeter of a rectangle is P = 2L + 2w. Substituting L = 2w and P = 120 into the formula gives 120 = 2(2w) + 2w. This can also be written as 2w + 2(2w) = 120.
Question 3
The measure of an angle is 18 degrees more than one-third the measure of its supplementary angle. If x is the measure of the angle, which equation correctly represents this relationship?
- x = (1/3)(90 - x) + 18
- x + (1/3)x + 18 = 180
- x = 3(180 - x) + 18
- x = (1/3)(180 - x) + 18 (correct answer)
Explanation: Let the angle be x. Its supplement is 180 - x. 'One-third the measure of its supplement' is (1/3)(180 - x). '18 degrees more than' this quantity is (1/3)(180 - x) + 18. Since this is equal to the measure of the angle x, the equation is x = (1/3)(180 - x) + 18.
Question 4
The temperature at 6:00 a.m. was -8°F. The temperature increased at a constant rate of 3°F per hour. Which equation can be used to find h, the number of hours it took for the temperature to reach 13°F?
- -8 + 3h = 13 (correct answer)
- -8 - 3h = 13
- 8 + 3h = 13
- 3h - 8 = 13
Explanation: The final temperature (13°F) is equal to the initial temperature (-8°F) plus the total increase. The total increase is the rate (3°F per hour) multiplied by the number of hours (h), which is 3h. So, the equation is -8 + 3h = 13.
Question 5
A train travels at 80 miles per hour for h hours, going D miles. Which equation is correct?
- D=80+h
- h=80D
- D=80h (correct answer)
- D=8h
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes a train traveling at 80 miles per hour for h hours, requiring an equation that shows distance equals rate times time (D = rt). Choice C is correct because D = 80h accurately models the relationship where distance equals the rate (80 mph) multiplied by time (h hours). Choice A incorrectly adds instead of multiplying, Choice B reverses the relationship making hours equal 80 times distance, and Choice D uses an incorrect rate of 8 instead of 80. To help students, reinforce the fundamental formula distance = rate × time and practice identifying which quantity is which in word problems. Common errors include confusing addition with multiplication in rate problems.
Question 6
A store has 150 dollars fixed costs and makes 9 dollars profit per product sold. For p products, which equation models R?
- R=150p+9
- R=150+9p (correct answer)
- R=150−9p
- R=9p
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes a store with 150fixedcoststhatmakes9 profit per product, requiring an equation of the form R = fixed costs + (profit per product × products). Choice B is correct because R = 150 + 9p accurately models starting with 150infixedcostsandadding9 profit for each of p products sold. Choice A incorrectly reverses the coefficients making it 150p + 9, Choice C subtracts the profit instead of adding it, and Choice D omits the fixed costs entirely. To help students, teach them to identify fixed versus variable components and understand that profits typically add to totals. Business contexts like this help students see real-world applications of linear equations.
Question 7
Maya starts with 120 dollars and saves 25 dollars monthly for m months, totaling T. Choose the equation.
- T=120+25m (correct answer)
- T=25+120m
- T=120−25m
- T=120+25
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes starting with 120andadding25 each month for m months, requiring an equation of the form T = initial amount + (monthly amount × months). Choice A is correct because T = 120 + 25m accurately models starting with 120andadding25 for each of m months. Choice B incorrectly reverses the constants, Choice C subtracts instead of adds, and Choice D doesn't include the variable m. To help students, emphasize identifying the starting value and the repeated action, then translating 'each month' or 'per month' into multiplication. Regular practice with savings and accumulation problems builds this skill.
Question 8
A lab uses 8 grams of Chemical A plus 3 grams per trial of Chemical B. For t trials, write G.
- G=8+3t (correct answer)
- G=(8+3)t
- G=8−3t
- G=3+8t
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes using 8 grams of Chemical A (fixed amount) plus 3 grams per trial of Chemical B, requiring an equation of the form G = fixed amount + (amount per trial × trials). Choice A is correct because G = 8 + 3t accurately models using 8 grams initially plus 3 grams for each of t trials. Choice B incorrectly groups the constants before multiplying, Choice C subtracts instead of adds, and Choice D reverses the coefficients. To help students, teach them to distinguish between fixed amounts (used once) and variable amounts (used repeatedly). Practice identifying keywords like 'per trial' or 'each time' that signal multiplication.
Question 9
A cyclist rides at 18 miles per hour for t hours. Which equation models distance d?
- d=18+t
- d=18t (correct answer)
- d=t18
- d=t−18
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes a constant speed of 18 miles per hour multiplied by time t to find distance d, requiring an equation of the form d = speed × time. Choice B is correct because it accurately models the relationship using multiplication of the given speed and time variable. Choice C is incorrect because it divides instead of multiplies, a common error when students invert the rate relationship. To help students, teach identifying key parts of scenarios like velocity and time, and translating them into mathematical terms. Encourage practice with varied contexts such as cycling or driving to build flexibility in model creation.
Question 10
A car travels at 55 miles per hour for t hours. What equation represents distance d?
- d=t55
- d=55t (correct answer)
- d=55+t
- d=t−55
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes a constant speed of 55 miles per hour multiplied by time t to find distance d, requiring an equation of the form d = speed × time. Choice B is correct because it accurately models the relationship using multiplication of the given speed and time variable. Choice A is incorrect because it uses division instead of multiplication, a common error when students confuse speed with rate formulas. To help students, teach identifying key parts of scenarios like rates and variables, and translating them into mathematical terms. Encourage practice with varied contexts such as travel or work rates to build flexibility in model creation.
Question 11
A runner moves at 7 miles per hour for t hours. Which equation gives distance d?
- d=7+t
- d=t7
- d=7t (correct answer)
- d=t−7
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes a constant speed of 7 miles per hour multiplied by time t to find distance d, requiring an equation of the form d = speed × time. Choice C is correct because it accurately models the relationship using multiplication of the given speed and time variable. Choice B is incorrect because it divides instead of multiplies, a common error when inverting the formula. To help students, teach identifying key parts of scenarios like pace and duration, and translating them into mathematical terms. Encourage practice with varied contexts such as running or walking to build flexibility in model creation.
Question 12
A bakery pays 60 dollars fixed costs and makes 3 dollars profit per cupcake sold. Identify P.
- P=60+3c
- P=3c−60 (correct answer)
- P=60c+3
- P=c3+60
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes profit of 3 dollars per cupcake minus fixed costs of 60 dollars for total P, requiring an equation of the form P = rate × items - fixed. Choice B is correct because it accurately models the relationship using multiplication for per-item profit and subtraction for costs. Choice A is incorrect because it adds the fixed cost, a common error when students confuse costs with revenues. To help students, teach identifying key parts of scenarios like profits and deductions, and translating them into mathematical terms. Encourage practice with varied contexts such as sales or production to build flexibility in model creation.
Question 13
Noah deposits 35 dollars, then saves 15 dollars each month for m months. Identify S.
- S=15+35m
- S=35−15m
- S=15m+35 (correct answer)
- S=m15+35
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes an initial deposit of 35 dollars plus 15 dollars added each month for m months, requiring an equation of the form S = rate × months + initial. Choice C is correct because it accurately models the relationship using multiplication for the monthly savings and addition for the initial deposit. Choice B is incorrect because it subtracts with swapped coefficients, a common error when misordering terms. To help students, teach identifying key parts of scenarios like initials and rates, and translating them into mathematical terms. Encourage practice with varied contexts such as finances or increments to build flexibility in model creation.
Question 14
A company has fixed costs of 500 dollars and earns 20 dollars per unit sold. Choose P.
- P=500+20u
- P=20u−500 (correct answer)
- P=500u+20
- P=u20−500
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes earnings of 20 dollars per unit minus fixed costs of 500 dollars for profit P, requiring an equation of the form P = rate × units - fixed. Choice B is correct because it accurately models the relationship using multiplication for earnings and subtraction for costs. Choice A is incorrect because it adds the fixed cost, a common error when confusing profit calculation. To help students, teach identifying key parts of scenarios like incomes and outflows, and translating them into mathematical terms. Encourage practice with varied contexts such as manufacturing or trade to build flexibility in model creation.
Question 15
Ava deposits 200 dollars, then saves 10 dollars each month for m months. Which is correct?
- S=200m+10
- S=200−10m
- S=10m+200 (correct answer)
- S=m200+10
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes an initial deposit of 200 dollars plus 10 dollars added each month for m months, requiring an equation of the form S = rate × months + initial. Choice C is correct because it accurately models the relationship using multiplication for the monthly savings and addition for the initial deposit. Choice B is incorrect because it subtracts with reversed terms, a common error when misinterpreting savings as spending. To help students, teach identifying key parts of scenarios like deposits and additions, and translating them into mathematical terms. Encourage practice with varied contexts such as accounts or collections to build flexibility in model creation.
Question 16
A kiosk pays 90 dollars fixed costs and earns 5 dollars profit per item sold. Which fits P?
- P=90+5n
- P=5n−90 (correct answer)
- P=90n+5
- P=n5+90
Explanation: This question tests middle-level math skills: choosing an equation to model a situation. Understanding equations involves recognizing relationships between variables and constants as described in a scenario. In this example, the scenario describes earnings of 5 dollars profit per item minus fixed costs of 90 dollars for total P, requiring an equation of the form P = rate × items - fixed. Choice B is correct because it accurately models the relationship using multiplication for per-item earnings and subtraction for costs. Choice A is incorrect because it adds the fixed cost, a common error in calculating net profit. To help students, teach identifying key parts of scenarios like profits and costs, and translating them into mathematical terms. Encourage practice with varied contexts such as kiosks or retail to build flexibility in model creation.
Question 17
The sum of three consecutive odd integers is 141. If n represents the smallest of these integers, which equation models this situation?
- n + (n + 1) + (n + 2) = 141
- n + (n + 2) + (n + 4) = 141 (correct answer)
- 3n + 3 = 141
- n(n + 2)(n + 4) = 141
Explanation: If n is the smallest odd integer, the next consecutive odd integer is n + 2, and the one after that is n + 4. The sum of these three integers is n + (n + 2) + (n + 4). Setting this sum equal to 141 gives the equation n + (n + 2) + (n + 4) = 141.
Question 18
A salesperson earns a base salary of 400perweekplusan8720. Which equation can be used to find S, her total sales in dollars for the week?
- 400 + 8S = 720
- 0.08(400 + S) = 720
- 400 + 0.08S = 720 (correct answer)
- 400S + 0.08 = 720
Explanation: The salesperson's total earnings are the sum of her base salary (400)andhercommission.Thecommissionis8720 is 400 + 0.08S = 720.
Question 19
Planning a party at a community center costs 15foraroomrentalplus9.50 per person attending. If the total budget for the party is $186, which equation determines the number of people, p, that can attend?
- 15p + 9.50 = 186
- (15 + 9.50)p = 186
- 9.50(p + 15) = 186
- 15 + 9.50p = 186 (correct answer)
Explanation: The total cost is composed of a fixed cost (the 15roomrental)andavariablecostthatdependsonthenumberofpeople.Thevariablecostis9.50 times the number of people, p, which is 9.50p. The total cost, which must equal the budget of $186, is the sum of these costs: 15 + 9.50p = 186.
Question 20
Maya's age is 5 years more than twice her brother's age. The sum of their ages is 32. Which equation can be used to find b, the brother's age?
- b + (2b - 5) = 32
- b + 2(b + 5) = 32
- 2b + 5 = 32
- b + (2b + 5) = 32 (correct answer)
Explanation: Let b be the brother's age. 'Twice her brother's age' is 2b. '5 years more than twice her brother's age' means Maya's age is 2b + 5. The sum of their ages is 32, which means the brother's age (b) plus Maya's age (2b + 5) equals 32. This gives the equation b + (2b + 5) = 32.