Adam pays $24.30 for 1 marble and 7 stickers.
The marble costs $1.90 more than each sticker.
- What is the cost of 1 marble?
- How much is the cost of 7 marbles and 4 stickers?
(a)
Choose the cheaper item to be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.90
Cost of 7 stickers
= 7 x 1 u
= 7 u
Total cost of 1 marble and 7 stickers
= 1 u + 1.90 + 7 u
= 8 u + 1.90
8 u + 1.90 = 24.30
8 u = 24.30 - 1.90
8 u = 22.40
1 u = 22.40 ÷ 8 = 2.80
Cost of 1 marble
= 2.80 + 1.90
= $4.70
(b)
Cost of 7 marbles and 4 stickers
= 7 x 4.70 + 4 x 2.80
= 32.90 + 11.20
= $44.10
Answer(s): (a) $4.70; (b) $44.10