Adam spends $12.70 on 2 stickers and 3 marbles.
A sticker costs $1.10 more than 1 marble.
- How much does 1 sticker cost?
- How much do 3 stickers cost?
- How much do a marble and 3 stickers cost?
- How much do 3 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 + 1.10
Total cost of 2 stickers and 3 marbles
= 2(1 u + 1.10) + 3 u
= 2 u + 2.20 + 3 u
= 2 u + 3 u + 2.20
= 5 u + 2.20
5 u + 2.20 = 12.70
5 u = 12.70 - 2.20
5 u = 10.50
1 u = 10.50 ÷ 5 = 2.10
Cost of 1 sticker
= 1 u + 1.10
= 2.10 + 1.10
= $3.20
(b)
Cost of 3 stickers
= 3 x 3.20
= $9.60
(c)
Cost of 1 marble and 3 stickers
= 2.10 + 9.60
= $11.70
(d)
Cost of 3 stickers more than 1 marble
= 9.60 - 2.10
= $7.50
Answer(s): (a) $3.20; (b) $9.60; (c) $11.70; (d) $7.50