Adam spends $12.40 on 4 stickers and 5 marbles.
A sticker costs $2.20 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 + 2.20
Total cost of 4 stickers and 5 marbles
= 4(1 u + 2.20) + 5 u
= 4 u + 8.80 + 5 u
= 4 u + 5 u + 8.80
= 9 u + 8.80
9 u + 8.80 = 12.40
9 u = 12.40 - 8.80
9 u = 3.60
1 u = 3.60 ÷ 9 = 0.40
Cost of 1 sticker
= 1 u + 2.20
= 0.40 + 2.20
= $2.60
(b)
Cost of 8 stickers
= 8 x 2.60
= $20.80
(c)
Cost of 1 marble and 8 stickers
= 0.40 + 20.80
= $21.20
(d)
Cost of 8 stickers more than 1 marble
= 20.80 - 0.40
= $20.40
Answer(s): (a) $2.60; (b) $20.80; (c) $21.20; (d) $20.40
