Adam spends $16.10 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 = 16.10
9 u = 16.10 - 4.40
9 u = 11.70
1 u = 11.70 ÷ 9 = 1.30
Cost of 1 sticker
= 1 u + 1.10
= 1.30 + 1.10
= $2.40
(b)
Cost of 8 stickers
= 8 x 2.40
= $19.20
(c)
Cost of 1 marble and 8 stickers
= 1.30 + 19.20
= $20.50
(d)
Cost of 8 stickers more than 1 marble
= 19.20 - 1.30
= $17.90
Answer(s): (a) $2.40; (b) $19.20; (c) $20.50; (d) $17.90