Adam pays $28.10 for 1 marble and 7 stickers.
The marble costs $2.50 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 2 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.50
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.50 + 7 u
= 8 u + 2.50
8 u + 2.50 = 28.10
8 u = 28.10 - 2.50
8 u = 25.60
1 u = 25.60 ÷ 8 = 3.20
Cost of 1 marble
= 3.20 + 2.50
= $5.70
(b)
Cost of 7 marbles and 2 stickers
= 7 x 5.70 + 2 x 3.20
= 39.90 + 6.40
= $46.30
Answer(s): (a) $5.70; (b) $46.30