Adam spends $16.10 on 2 marbles and 3 stickers.
A marble costs $2.80 more than 1 sticker.
- How much does 1 marble cost?
- How much do 3 marbles cost?
- How much do a sticker and 3 marbles cost?
- How much do 3 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 + 2.80
Total cost of 2 marbles and 3 stickers
= 2(1 u + 2.80) + 3 u
= 2 u + 5.60 + 3 u
= 2 u + 3 u + 5.60
= 5 u + 5.60
5 u + 5.60 = 16.10
5 u = 16.10 - 5.60
5 u = 10.50
1 u = 10.50 ÷ 5 = 2.10
Cost of 1 marble
= 1 u + 2.80
= 2.10 + 2.80
= $4.90
(b)
Cost of 3 marbles
= 3 x 4.90
= $14.70
(c)
Cost of 1 sticker and 3 marbles
= 2.10 + 14.70
= $16.80
(d)
Cost of 3 marbles more than 1 sticker
= 14.70 - 2.10
= $12.60
Answer(s): (a) $4.90; (b) $14.70; (c) $16.80; (d) $12.60