Adam spends $13.30 on 3 stickers and 4 marbles.
A sticker costs $1.40 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 + 1.40
Total cost of 3 stickers and 4 marbles
= 3(1 u + 1.40) + 4 u
= 3 u + 4.20 + 4 u
= 3 u + 4 u + 4.20
= 7 u + 4.20
7 u + 4.20 = 13.30
7 u = 13.30 - 4.20
7 u = 9.10
1 u = 9.10 ÷ 7 = 1.30
Cost of 1 sticker
= 1 u + 1.40
= 1.30 + 1.40
= $2.70
(b)
Cost of 6 stickers
= 6 x 2.70
= $16.20
(c)
Cost of 1 marble and 6 stickers
= 1.30 + 16.20
= $17.50
(d)
Cost of 6 stickers more than 1 marble
= 16.20 - 1.30
= $14.90
Answer(s): (a) $2.70; (b) $16.20; (c) $17.50; (d) $14.90