Adam pays $42.10 for 1 marble and 7 stickers.
The marble costs $2.90 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 5 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.90
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.90 + 7 u
= 8 u + 2.90
8 u + 2.90 = 42.10
8 u = 42.10 - 2.90
8 u = 39.20
1 u = 39.20 ÷ 8 = 4.90
Cost of 1 marble
= 4.90 + 2.90
= $7.80
(b)
Cost of 7 marbles and 5 stickers
= 7 x 7.80 + 5 x 4.90
= 54.60 + 24.50
= $79.10
Answer(s): (a) $7.80; (b) $79.10