Adam spends $14.80 on 4 stickers and 5 marbles.
A sticker costs $1.90 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 + 1.90
Total cost of 4 stickers and 5 marbles
= 4(1 u + 1.90) + 5 u
= 4 u + 7.60 + 5 u
= 4 u + 5 u + 7.60
= 9 u + 7.60
9 u + 7.60 = 14.80
9 u = 14.80 - 7.60
9 u = 7.20
1 u = 7.20 ÷ 9 = 0.80
Cost of 1 sticker
= 1 u + 1.90
= 0.80 + 1.90
= $2.70
(b)
Cost of 8 stickers
= 8 x 2.70
= $21.60
(c)
Cost of 1 marble and 8 stickers
= 0.80 + 21.60
= $22.40
(d)
Cost of 8 stickers more than 1 marble
= 21.60 - 0.80
= $20.80
Answer(s): (a) $2.70; (b) $21.60; (c) $22.40; (d) $20.80