Adam pays $42.70 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 = 42.70
5 u = 42.70 - 2.20
5 u = 40.50
1 u = 40.50 ÷ 5 = 8.10
Cost of 1 marble
= 8.10 + 2.20
= $10.30
(b)
Cost of 4 marbles and 7 stickers
= 4 x 10.30 + 7 x 8.10
= 41.20 + 56.70
= $97.90
Answer(s): (a) $10.30; (b) $97.90