Mrs. Gupta received a 2% per hour cost of living increase. She was earning d dollars per hour before the increase. Which expression represents Mrs. Gupta's new hourly wage?

A. d − 0.2d
Incorrect. She received an increase in wages not a decrease so the operation should be addition.

B. d + 0.2d
Incorrect. 2% should be written as 0.02.

C. d − 0.02d
Incorrect. She received an increase in wages not a decrease so the operation should be addition.

D. d + 0.02d
Correct! Her original earnings, d, would increase by 2% or 0.02d.

The gift store had 8 types of gift bags and 12 types of wrapping paper. The gift bags sold for x dollars and the wrapping paper sold for y dollars. Which expression gives the average price per each item at the gift store?

1. 8x + 12y 20
2. 8x + 12y
3. 12x + 8y 20
4. 20(x + y)

A.
Correct! The total cost (8x + 12y) would be divided by the total number of items (20) to determine the average cost.

B.
Incorrect. You need to find the “average price” per item not the cost of all items so the sum should be divided by 20.

C.
Incorrect. There are 8 types of gift bags (x) and 12 types of wrapping paper (y).

D.
Incorrect. You need to find the “average price” per item not the sum of the costs.

The area of the unshaded portion of the rectangle shown below is 30x.

How can the area of the shaded region of the rectangle be expressed in terms of x?

1. 30x(75)
2. 30(75 − x)
3. 12x + 8y 20
4. 20(x + y)

A.
Incorrect. This is the area of both rectangles together.

B.
Correct! The length of the rectangle (30) would be multiplied by the width of the rectangle (75 – x) to find the area of the shaded region.

C.
Incorrect. The area of the shaded region is 30(75 – x).

D.
Incorrect. The area of the shaded region is 30(75 – x).

A popcorn vendor sold popcorn at a sports event for $2.00 per bag. At the end of the event, he had $684.00. This total included the $100 in change that he started with. Which equation could be used to find b, the number of bags of popcorn sold?

A. 684 = 2b
Incorrect. The $100 received in change needs to included in the equation.

B. 684 = 100 − 2b
Incorrect. The cost of each bag of popcorn, 2b, and the $100 in change should equal $684.

C. 684 = 2b + 100
Correct! The vendor began the day with $100 and made $2b in bags of popcorn for a total of $684.

D. 684 + 100 = 2b
Incorrect. The $100 received in change should be subtracted from the total money earned.

The length of a rectangle is 5 less than 3 times the width of the rectangle. If the perimeter of the rectangle is 62 centimeters, which equation could be used to find w, the width of the rectangle?

A. w + 5 − 3w = 62
Incorrect. To find perimeter, you should double the width and the length.

B. w + 3w − 5 = 62
Incorrect. To find perimeter, you should double the width and the length.

C. 2(w) + 2(5 − 3w) = 62
Incorrect. “5 less than 3 times the width” should be written as 3w – 5.

D. 2(w) + 2(3w − 5) = 62
Correct! The perimeter, 62, will be found by multiplying 2 times the width, w, plus 2 times the length (3w – 5).