Adam spends $13.70 on 2 stickers and 3 marbles.
A sticker costs $1.60 more than 1 marble.
- How much does 1 sticker cost?
- How much do 8 stickers cost?
- How much do a marble and 8 stickers cost?
- How much do 8 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 + 1.60
Total cost of 2 stickers and 3 marbles
= 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 = 13.70
5 u = 13.70 - 3.20
5 u = 10.50
1 u = 10.50 ÷ 5 = 2.10
Cost of 1 sticker
= 1 u + 1.60
= 2.10 + 1.60
= $3.70
(b)
Cost of 8 stickers
= 8 x 3.70
= $29.60
(c)
Cost of 1 marble and 8 stickers
= 2.10 + 29.60
= $31.70
(d)
Cost of 8 stickers more than 1 marble
= 29.60 - 2.10
= $27.50
Answer(s): (a) $3.70; (b) $29.60; (c) $31.70; (d) $27.50