Adam pays $23.10 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 6 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 = 23.10
9 u = 23.10 - 2.40
9 u = 20.70
1 u = 20.70 ÷ 9 = 2.30
Cost of 1 marble
= 2.30 + 2.40
= $4.70
(b)
Cost of 8 marbles and 6 stickers
= 8 x 4.70 + 6 x 2.30
= 37.60 + 13.80
= $51.40
Answer(s): (a) $4.70; (b) $51.40