Adam spends $15.20 on 4 stickers and 5 marbles.
A sticker costs $1.10 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 + 1.10
Total cost of 4 stickers and 5 marbles
= 4(1 u + 1.10) + 5 u
= 4 u + 4.40 + 5 u
= 4 u + 5 u + 4.40
= 9 u + 4.40
9 u + 4.40 = 15.20
9 u = 15.20 - 4.40
9 u = 10.80
1 u = 10.80 ÷ 9 = 1.20
Cost of 1 sticker
= 1 u + 1.10
= 1.20 + 1.10
= $2.30
(b)
Cost of 8 stickers
= 8 x 2.30
= $18.40
(c)
Cost of 1 marble and 8 stickers
= 1.20 + 18.40
= $19.60
(d)
Cost of 8 stickers more than 1 marble
= 18.40 - 1.20
= $17.20
Answer(s): (a) $2.30; (b) $18.40; (c) $19.60; (d) $17.20