Adam spends $14.30 on 2 stickers and 3 marbles.
A sticker costs $2.90 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 + 2.90
Total cost of 2 stickers and 3 marbles
= 2(1 u + 2.90) + 3 u
= 2 u + 5.80 + 3 u
= 2 u + 3 u + 5.80
= 5 u + 5.80
5 u + 5.80 = 14.30
5 u = 14.30 - 5.80
5 u = 8.50
1 u = 8.50 ÷ 5 = 1.70
Cost of 1 sticker
= 1 u + 2.90
= 1.70 + 2.90
= $4.60
(b)
Cost of 7 stickers
= 7 x 4.60
= $32.20
(c)
Cost of 1 marble and 7 stickers
= 1.70 + 32.20
= $33.90
(d)
Cost of 7 stickers more than 1 marble
= 32.20 - 1.70
= $30.50
Answer(s): (a) $4.60; (b) $32.20; (c) $33.90; (d) $30.50