Adam pays $41.40 for 1 marble and 7 stickers.
The marble costs $2.20 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 8 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 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.20 + 7 u
= 8 u + 2.20
8 u + 2.20 = 41.40
8 u = 41.40 - 2.20
8 u = 39.20
1 u = 39.20 ÷ 8 = 4.90
Cost of 1 marble
= 4.90 + 2.20
= $7.10
(b)
Cost of 7 marbles and 8 stickers
= 7 x 7.10 + 8 x 4.90
= 49.70 + 39.20
= $88.90
Answer(s): (a) $7.10; (b) $88.90