Mary paid $280 for some cupcakes and cookies. The ratio of the boxes of cupcakes to the boxes of cookies was 3 : 5. Each box of cupcakes cost $5 more than each box of cookies. She paid $80 more for the cupcakes than the cookies. What was the price of each box of cupcakes?
(a)
Total amount that the cookies cost
= (280 - 80) ÷ 2
= 200 ÷ 2
= $100

Total amount that the cupcakes cost
= 100 + 80
= $180

Number of sets of cupcakes = 3
Number of sets of cookies = 5

Cost of 1 set of cupcakes
= 180 ÷ 3
= $60

Cost of 1 set of cookies
= 100 ÷ 5
= $20

Amount that 1 set of cupcakes cost more than 1 set of cookies
= 60 - 20
= $40

Number of boxes of cupcakes in 1 set
= 40 ÷ 5
= 8

Price of each box of cupcakes
= 60 ÷ 8
= $7.50

Answer(s): $7.50