Adam spends $15.20 on 4 marbles and 5 stickers.
A marble costs $2.90 more than 1 sticker.
- How much does 1 marble cost?
- How much do 5 marbles cost?
- How much do a sticker and 5 marbles cost?
- How much do 5 marbles cost more than 1 sticker?
(a)
Let the cheaper item be 1 u.
Cost of 1 sticker = 1 u
Cost of 1 marble = 1 u + 2.90
Total cost of 4 marbles and 5 stickers
= 4(1 u + 2.90) + 5 u
= 4 u + 11.60 + 5 u
= 4 u + 5 u + 11.60
= 9 u + 11.60
9 u + 11.60 = 15.20
9 u = 15.20 - 11.60
9 u = 3.60
1 u = 3.60 ÷ 9 = 0.40
Cost of 1 marble
= 1 u + 2.90
= 0.40 + 2.90
= $3.30
(b)
Cost of 5 marbles
= 5 x 3.30
= $16.50
(c)
Cost of 1 sticker and 5 marbles
= 0.40 + 16.50
= $16.90
(d)
Cost of 5 marbles more than 1 sticker
= 16.50 - 0.40
= $16.10
Answer(s): (a) $3.30; (b) $16.50; (c) $16.90; (d) $16.10
