Adam pays $28.50 for 1 marble and 5 stickers.
The marble costs $2.10 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 5 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 + 2.10
Cost of 5 stickers
= 5 x 1 u
= 5 u
Total cost of 1 marble and 5 stickers
= 1 u + 2.10 + 5 u
= 6 u + 2.10
6 u + 2.10 = 28.50
6 u = 28.50 - 2.10
6 u = 26.40
1 u = 26.40 ÷ 6 = 4.40
Cost of 1 marble
= 4.40 + 2.10
= $6.50
(b)
Cost of 5 marbles and 7 stickers
= 5 x 6.50 + 7 x 4.40
= 32.50 + 30.80
= $63.30
Answer(s): (a) $6.50; (b) $63.30