Adam pays $28.70 for 1 marble and 4 stickers.
The marble costs $2.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 4 marbles and 7 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.20
Cost of 4 stickers
= 4 x 1 u
= 4 u
Total cost of 1 marble and 4 stickers
= 1 u + 2.20 + 4 u
= 5 u + 2.20
5 u + 2.20 = 28.70
5 u = 28.70 - 2.20
5 u = 26.50
1 u = 26.50 ÷ 5 = 5.30
Cost of 1 marble
= 5.30 + 2.20
= $7.50
(b)
Cost of 4 marbles and 7 stickers
= 4 x 7.50 + 7 x 5.30
= 30.00 + 37.10
= $67.10
Answer(s): (a) $7.50; (b) $67.10