Adam pays $24.90 for 1 marble and 8 stickers.
The marble costs $2.40 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 2.40
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.40 + 8 u
= 9 u + 2.40
9 u + 2.40 = 24.90
9 u = 24.90 - 2.40
9 u = 22.50
1 u = 22.50 ÷ 9 = 2.50
Cost of 1 marble
= 2.50 + 2.40
= $4.90
(b)
Cost of 8 marbles and 5 stickers
= 8 x 4.90 + 5 x 2.50
= 39.20 + 12.50
= $51.70
Answer(s): (a) $4.90; (b) $51.70