Adam spends $15.30 on 2 stickers and 3 marbles.
A sticker costs $1.40 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 + 1.40
Total cost of 2 stickers and 3 marbles
= 2(1 u + 1.40) + 3 u
= 2 u + 2.80 + 3 u
= 2 u + 3 u + 2.80
= 5 u + 2.80
5 u + 2.80 = 15.30
5 u = 15.30 - 2.80
5 u = 12.50
1 u = 12.50 ÷ 5 = 2.50
Cost of 1 sticker
= 1 u + 1.40
= 2.50 + 1.40
= $3.90
(b)
Cost of 8 stickers
= 8 x 3.90
= $31.20
(c)
Cost of 1 marble and 8 stickers
= 2.50 + 31.20
= $33.70
(d)
Cost of 8 stickers more than 1 marble
= 31.20 - 2.50
= $28.70
Answer(s): (a) $3.90; (b) $31.20; (c) $33.70; (d) $28.70