Adam pays $22.50 for 1 marble and 8 stickers.
The marble costs $2.70 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 marbles and 2 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.70
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.70 + 8 u
= 9 u + 2.70
9 u + 2.70 = 22.50
9 u = 22.50 - 2.70
9 u = 19.80
1 u = 19.80 ÷ 9 = 2.20
Cost of 1 marble
= 2.20 + 2.70
= $4.90
(b)
Cost of 8 marbles and 2 stickers
= 8 x 4.90 + 2 x 2.20
= 39.20 + 4.40
= $43.60
Answer(s): (a) $4.90; (b) $43.60