Adam pays $33.50 for 1 marble and 8 stickers.
The marble costs $1.10 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 8 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 + 1.10
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 1.10 + 8 u
= 9 u + 1.10
9 u + 1.10 = 33.50
9 u = 33.50 - 1.10
9 u = 32.40
1 u = 32.40 ÷ 9 = 3.60
Cost of 1 marble
= 3.60 + 1.10
= $4.70
(b)
Cost of 8 marbles and 7 stickers
= 8 x 4.70 + 7 x 3.60
= 37.60 + 25.20
= $62.80
Answer(s): (a) $4.70; (b) $62.80