Adam spends $12.70 on 3 stickers and 4 marbles.
A sticker costs $2.60 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 + 2.60
Total cost of 3 stickers and 4 marbles
= 3(1 u + 2.60) + 4 u
= 3 u + 7.80 + 4 u
= 3 u + 4 u + 7.80
= 7 u + 7.80
7 u + 7.80 = 12.70
7 u = 12.70 - 7.80
7 u = 4.90
1 u = 4.90 ÷ 7 = 0.70
Cost of 1 sticker
= 1 u + 2.60
= 0.70 + 2.60
= $3.30
(b)
Cost of 8 stickers
= 8 x 3.30
= $26.40
(c)
Cost of 1 marble and 8 stickers
= 0.70 + 26.40
= $27.10
(d)
Cost of 8 stickers more than 1 marble
= 26.40 - 0.70
= $25.70
Answer(s): (a) $3.30; (b) $26.40; (c) $27.10; (d) $25.70