Adam spends $14.90 on 3 stickers and 4 marbles.
A sticker costs $1.70 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 + 1.70
Total cost of 3 stickers and 4 marbles
= 3(1 u + 1.70) + 4 u
= 3 u + 5.10 + 4 u
= 3 u + 4 u + 5.10
= 7 u + 5.10
7 u + 5.10 = 14.90
7 u = 14.90 - 5.10
7 u = 9.80
1 u = 9.80 ÷ 7 = 1.40
Cost of 1 sticker
= 1 u + 1.70
= 1.40 + 1.70
= $3.10
(b)
Cost of 8 stickers
= 8 x 3.10
= $24.80
(c)
Cost of 1 marble and 8 stickers
= 1.40 + 24.80
= $26.20
(d)
Cost of 8 stickers more than 1 marble
= 24.80 - 1.40
= $23.40
Answer(s): (a) $3.10; (b) $24.80; (c) $26.20; (d) $23.40
