Adam spends $16.90 on 3 stickers and 4 marbles.
A sticker costs $2.60 more than 1 marble.
- How much does 1 sticker cost?
- How much do 4 stickers cost?
- How much do a marble and 4 stickers cost?
- How much do 4 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 + 2.60
Total cost of 3 stickers and 4 marbles
= 3(1 u + 2.60) + 4 u
= 3 u + 7.80 + 4 u
= 3 u + 4 u + 7.80
= 7 u + 7.80
7 u + 7.80 = 16.90
7 u = 16.90 - 7.80
7 u = 9.10
1 u = 9.10 ÷ 7 = 1.30
Cost of 1 sticker
= 1 u + 2.60
= 1.30 + 2.60
= $3.90
(b)
Cost of 4 stickers
= 4 x 3.90
= $15.60
(c)
Cost of 1 marble and 4 stickers
= 1.30 + 15.60
= $16.90
(d)
Cost of 4 stickers more than 1 marble
= 15.60 - 1.30
= $14.30
Answer(s): (a) $3.90; (b) $15.60; (c) $16.90; (d) $14.30