Adam pays $43.60 for 1 marble and 4 stickers.
The marble costs $2.10 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 + 2.10
Cost of 4 stickers
= 4 x 1 u
= 4 u
Total cost of 1 marble and 4 stickers
= 1 u + 2.10 + 4 u
= 5 u + 2.10
5 u + 2.10 = 43.60
5 u = 43.60 - 2.10
5 u = 41.50
1 u = 41.50 ÷ 5 = 8.30
Cost of 1 marble
= 8.30 + 2.10
= $10.40
(b)
Cost of 4 marbles and 7 stickers
= 4 x 10.40 + 7 x 8.30
= 41.60 + 58.10
= $99.70
Answer(s): (a) $10.40; (b) $99.70