Adam pays $27.80 for 1 marble and 8 stickers.
The marble costs $1.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 4 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.70
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 1.70 + 8 u
= 9 u + 1.70
9 u + 1.70 = 27.80
9 u = 27.80 - 1.70
9 u = 26.10
1 u = 26.10 ÷ 9 = 2.90
Cost of 1 marble
= 2.90 + 1.70
= $4.60
(b)
Cost of 8 marbles and 4 stickers
= 8 x 4.60 + 4 x 2.90
= 36.80 + 11.60
= $48.40
Answer(s): (a) $4.60; (b) $48.40