Adam pays $41.40 for 1 marble and 4 stickers.
The marble costs $2.90 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 + 2.90
Cost of 4 stickers
= 4 x 1 u
= 4 u
Total cost of 1 marble and 4 stickers
= 1 u + 2.90 + 4 u
= 5 u + 2.90
5 u + 2.90 = 41.40
5 u = 41.40 - 2.90
5 u = 38.50
1 u = 38.50 ÷ 5 = 7.70
Cost of 1 marble
= 7.70 + 2.90
= $10.60
(b)
Cost of 4 marbles and 7 stickers
= 4 x 10.60 + 7 x 7.70
= 42.40 + 53.90
= $96.30
Answer(s): (a) $10.60; (b) $96.30