Adam spends $14.80 on 5 stickers and 6 marbles.
A sticker costs $2.30 more than 1 marble.
- How much does 1 sticker cost?
- How much do 7 stickers cost?
- How much do a marble and 7 stickers cost?
- How much do 7 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 + 2.30
Total cost of 5 stickers and 6 marbles
= 5(1 u + 2.30) + 6 u
= 5 u + 11.50 + 6 u
= 5 u + 6 u + 11.50
= 11 u + 11.50
11 u + 11.50 = 14.80
11 u = 14.80 - 11.50
11 u = 3.30
1 u = 3.30 ÷ 11 = 0.30
Cost of 1 sticker
= 1 u + 2.30
= 0.30 + 2.30
= $2.60
(b)
Cost of 7 stickers
= 7 x 2.60
= $18.20
(c)
Cost of 1 marble and 7 stickers
= 0.30 + 18.20
= $18.50
(d)
Cost of 7 stickers more than 1 marble
= 18.20 - 0.30
= $17.90
Answer(s): (a) $2.60; (b) $18.20; (c) $18.50; (d) $17.90