Adam spends $14.90 on 4 stickers and 5 marbles.
A sticker costs $1.70 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 + 1.70
Total cost of 4 stickers and 5 marbles
= 4(1 u + 1.70) + 5 u
= 4 u + 6.80 + 5 u
= 4 u + 5 u + 6.80
= 9 u + 6.80
9 u + 6.80 = 14.90
9 u = 14.90 - 6.80
9 u = 8.10
1 u = 8.10 ÷ 9 = 0.90
Cost of 1 sticker
= 1 u + 1.70
= 0.90 + 1.70
= $2.60
(b)
Cost of 6 stickers
= 6 x 2.60
= $15.60
(c)
Cost of 1 marble and 6 stickers
= 0.90 + 15.60
= $16.50
(d)
Cost of 6 stickers more than 1 marble
= 15.60 - 0.90
= $14.70
Answer(s): (a) $2.60; (b) $15.60; (c) $16.50; (d) $14.70