Adam pays $36.70 for 1 marble and 7 stickers.
The marble costs $2.30 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 3 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.30
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 2.30 + 7 u
= 8 u + 2.30
8 u + 2.30 = 36.70
8 u = 36.70 - 2.30
8 u = 34.40
1 u = 34.40 ÷ 8 = 4.30
Cost of 1 marble
= 4.30 + 2.30
= $6.60
(b)
Cost of 7 marbles and 3 stickers
= 7 x 6.60 + 3 x 4.30
= 46.20 + 12.90
= $59.10
Answer(s): (a) $6.60; (b) $59.10