Adam pays $32.50 for 1 marble and 7 stickers.
The marble costs $1.30 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 8 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.30
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.30 + 7 u
= 8 u + 1.30
8 u + 1.30 = 32.50
8 u = 32.50 - 1.30
8 u = 31.20
1 u = 31.20 ÷ 8 = 3.90
Cost of 1 marble
= 3.90 + 1.30
= $5.20
(b)
Cost of 7 marbles and 8 stickers
= 7 x 5.20 + 8 x 3.90
= 36.40 + 31.20
= $67.60
Answer(s): (a) $5.20; (b) $67.60