Adam pays $42.10 for 1 marble and 8 stickers.
The marble costs $2.50 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 + 2.50
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.50 + 8 u
= 9 u + 2.50
9 u + 2.50 = 42.10
9 u = 42.10 - 2.50
9 u = 39.60
1 u = 39.60 ÷ 9 = 4.40
Cost of 1 marble
= 4.40 + 2.50
= $6.90
(b)
Cost of 8 marbles and 5 stickers
= 8 x 6.90 + 5 x 4.40
= 55.20 + 22.00
= $77.20
Answer(s): (a) $6.90; (b) $77.20