Adam spends $15.90 on 2 stickers and 3 marbles.
A sticker costs $1.70 more than 1 marble.
- How much does 1 sticker cost?
- How much do 6 stickers cost?
- How much do a marble and 6 stickers cost?
- How much do 6 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 2 stickers and 3 marbles
= 2(1 u + 1.70) + 3 u
= 2 u + 3.40 + 3 u
= 2 u + 3 u + 3.40
= 5 u + 3.40
5 u + 3.40 = 15.90
5 u = 15.90 - 3.40
5 u = 12.50
1 u = 12.50 ÷ 5 = 2.50
Cost of 1 sticker
= 1 u + 1.70
= 2.50 + 1.70
= $4.20
(b)
Cost of 6 stickers
= 6 x 4.20
= $25.20
(c)
Cost of 1 marble and 6 stickers
= 2.50 + 25.20
= $27.70
(d)
Cost of 6 stickers more than 1 marble
= 25.20 - 2.50
= $22.70
Answer(s): (a) $4.20; (b) $25.20; (c) $27.70; (d) $22.70