Adam pays $32.30 for 1 marble and 8 stickers.
The marble costs $2.60 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 + 2.60
Cost of 8 stickers
= 8 x 1 u
= 8 u
Total cost of 1 marble and 8 stickers
= 1 u + 2.60 + 8 u
= 9 u + 2.60
9 u + 2.60 = 32.30
9 u = 32.30 - 2.60
9 u = 29.70
1 u = 29.70 ÷ 9 = 3.30
Cost of 1 marble
= 3.30 + 2.60
= $5.90
(b)
Cost of 8 marbles and 7 stickers
= 8 x 5.90 + 7 x 3.30
= 47.20 + 23.10
= $70.30
Answer(s): (a) $5.90; (b) $70.30