The number of minutes Angie works on math homework each night, m, is 30 more than the number of minutes she spends on science homework, s. Which equation represents the number of minutes she spends on science homework?

A. s = m – 30
Correct! Since she spends 30 minutes more on the math homework than the science homework, the 30 must be subtracted from math, m, to equal science, s.

B. s = m + 30
Incorrect. Since she spends 30 minutes more on the math homework than the science homework, the 30 must be subtracted from math, m, to equal science, s.

C. m = s – 30
Incorrect. Since she spends 30 minutes more on the math homework than the science homework, the 30 must be subtracted from math, m, to equal science, s.

D. m = 30s
Incorrect. Since she spends 30 minutes more on the math homework than the science homework, the 30 must be subtracted from math, m, to equal science, s.

Sebastian went to the department store to buy shoes that were on sale for 40% off the original price, x. Which equation can be used to find y, the sale price of the shoes, not including tax?

A. y = x – 0.6x
Incorrect. Multiplying the original price by 0.6 gives the sale price, there is no need to subtract it from the original price. An equation that is equivalent to 0.6x will be the answer.

B. y = x – 0.4x
Correct! Forty percent is represented as 0.4 and must be multiplied by the original price, x, to get the discount. The discount must be subtracted from the original price.

C. y = 0.4x
Incorrect. This will give the discount, you must now subtract the discount from the original price, x.

D. y = x + 0.4x
Incorrect. The discount must be subtracted from the original price, x. This answer choice adds the discount to the original price.

Ben wants to take art lessons. He pays $125 for his one time supply fee and is charged $35 per lesson. What will be the cost, c, if he takes n number of art lessons?

A. c = 125n + 35
Incorrect. Multiply the cost of each lesson, $35, by the number of lessons, n. Then add the supply fee, $125.

B. c = 125n + 35n
Incorrect. Multiply the cost of each lesson, $35, by the number of lessons, n. Then add the supply fee, $125.

C. c = 125 + 35n
Correct! Multiply the cost of each lesson, $35, by the number of lessons, n. Then add the supply fee, $125.

D. c = 35n
Incorrect. Multiply the cost of each lesson, $35, by the number of lessons, n. Then add the supply fee, $125.

Jo Ann's friends are going tubing on the Guadalupe River. The River Rafting Company charges $5 per tube per day and a $25 deposit per group. How much will it cost, c, for n number of friends to rent tubes for the day?

A. c = 25n + 5
Incorrect. Multiply the cost per tube, $5, by the number of friends, n, and then add the deposit, $25.

B. c = 5n + 25n
Incorrect. Multiply the cost per tube, $5, by the number of friends, n, and then add the deposit, $25.

C. c = 5n + 25
Correct! Multiply the cost per tube, $5, by the number of friends, n, and then add the deposit, $25.

D. c = 25n
Incorrect. Multiply the cost per tube, $5, by the number of friends, n, and then add the deposit, $25.