Adam spends $12.70 on 2 stickers and 3 marbles.
A sticker costs $2.60 more than 1 marble.
- How much does 1 sticker cost?
- How much do 7 stickers cost?
- How much do a marble and 7 stickers cost?
- How much do 7 stickers cost more than 1 marble?
(a)
Let the cheaper item be 1 u.
Cost of 1 marble = 1 u
Cost of 1 sticker = 1 u + 2.60
Total cost of 2 stickers and 3 marbles
= 2(1 u + 2.60) + 3 u
= 2 u + 5.20 + 3 u
= 2 u + 3 u + 5.20
= 5 u + 5.20
5 u + 5.20 = 12.70
5 u = 12.70 - 5.20
5 u = 7.50
1 u = 7.50 ÷ 5 = 1.50
Cost of 1 sticker
= 1 u + 2.60
= 1.50 + 2.60
= $4.10
(b)
Cost of 7 stickers
= 7 x 4.10
= $28.70
(c)
Cost of 1 marble and 7 stickers
= 1.50 + 28.70
= $30.20
(d)
Cost of 7 stickers more than 1 marble
= 28.70 - 1.50
= $27.20
Answer(s): (a) $4.10; (b) $28.70; (c) $30.20; (d) $27.20