Adam spends $16.70 on 3 stickers and 4 marbles.
A sticker costs $2.30 more than 1 marble.
- How much does 1 sticker cost?
- How much do 5 stickers cost?
- How much do a marble and 5 stickers cost?
- How much do 5 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 + 2.30
Total cost of 3 stickers and 4 marbles
= 3(1 u + 2.30) + 4 u
= 3 u + 6.90 + 4 u
= 3 u + 4 u + 6.90
= 7 u + 6.90
7 u + 6.90 = 16.70
7 u = 16.70 - 6.90
7 u = 9.80
1 u = 9.80 ÷ 7 = 1.40
Cost of 1 sticker
= 1 u + 2.30
= 1.40 + 2.30
= $3.70
(b)
Cost of 5 stickers
= 5 x 3.70
= $18.50
(c)
Cost of 1 marble and 5 stickers
= 1.40 + 18.50
= $19.90
(d)
Cost of 5 stickers more than 1 marble
= 18.50 - 1.40
= $17.10
Answer(s): (a) $3.70; (b) $18.50; (c) $19.90; (d) $17.10
