Adam spends $14.70 on 2 marbles and 3 stickers.
A marble costs $1.60 more than 1 sticker.
- How much does 1 marble cost?
- How much do 8 marbles cost?
- How much do a sticker and 8 marbles cost?
- How much do 8 marbles cost more than 1 sticker?
(a)
Let the cheaper item be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 1.60
Total cost of 2 marbles and 3 stickers
= 2(1 u + 1.60) + 3 u
= 2 u + 3.20 + 3 u
= 2 u + 3 u + 3.20
= 5 u + 3.20
5 u + 3.20 = 14.70
5 u = 14.70 - 3.20
5 u = 11.50
1 u = 11.50 ÷ 5 = 2.30
Cost of 1 marble
= 1 u + 1.60
= 2.30 + 1.60
= $3.90
(b)
Cost of 8 marbles
= 8 x 3.90
= $31.20
(c)
Cost of 1 sticker and 8 marbles
= 2.30 + 31.20
= $33.50
(d)
Cost of 8 marbles more than 1 sticker
= 31.20 - 2.30
= $28.90
Answer(s): (a) $3.90; (b) $31.20; (c) $33.50; (d) $28.90