Adam spends $16.10 on 5 stickers and 6 marbles.
A sticker costs $1.90 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 + 1.90
Total cost of 5 stickers and 6 marbles
= 5(1 u + 1.90) + 6 u
= 5 u + 9.50 + 6 u
= 5 u + 6 u + 9.50
= 11 u + 9.50
11 u + 9.50 = 16.10
11 u = 16.10 - 9.50
11 u = 6.60
1 u = 6.60 ÷ 11 = 0.60
Cost of 1 sticker
= 1 u + 1.90
= 0.60 + 1.90
= $2.50
(b)
Cost of 7 stickers
= 7 x 2.50
= $17.50
(c)
Cost of 1 marble and 7 stickers
= 0.60 + 17.50
= $18.10
(d)
Cost of 7 stickers more than 1 marble
= 17.50 - 0.60
= $16.90
Answer(s): (a) $2.50; (b) $17.50; (c) $18.10; (d) $16.90