Adam pays $32.50 for 1 marble and 7 stickers.
The marble costs $2.10 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 3 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.10
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.10 + 7 u
= 8 u + 2.10
8 u + 2.10 = 32.50
8 u = 32.50 - 2.10
8 u = 30.40
1 u = 30.40 ÷ 8 = 3.80
Cost of 1 marble
= 3.80 + 2.10
= $5.90
(b)
Cost of 7 marbles and 3 stickers
= 7 x 5.90 + 3 x 3.80
= 41.30 + 11.40
= $52.70
Answer(s): (a) $5.90; (b) $52.70