Adam spends $12.90 on 2 stickers and 3 marbles.
A sticker costs $1.20 more than 1 marble.
- How much does 1 sticker cost?
- How much do 6 stickers cost?
- How much do a marble and 6 stickers cost?
- How much do 6 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 + 1.20
Total cost of 2 stickers and 3 marbles
= 2(1 u + 1.20) + 3 u
= 2 u + 2.40 + 3 u
= 2 u + 3 u + 2.40
= 5 u + 2.40
5 u + 2.40 = 12.90
5 u = 12.90 - 2.40
5 u = 10.50
1 u = 10.50 ÷ 5 = 2.10
Cost of 1 sticker
= 1 u + 1.20
= 2.10 + 1.20
= $3.30
(b)
Cost of 6 stickers
= 6 x 3.30
= $19.80
(c)
Cost of 1 marble and 6 stickers
= 2.10 + 19.80
= $21.90
(d)
Cost of 6 stickers more than 1 marble
= 19.80 - 2.10
= $17.70
Answer(s): (a) $3.30; (b) $19.80; (c) $21.90; (d) $17.70