Adam spends $16.90 on 2 marbles and 3 stickers.
A marble costs $1.20 more than 1 sticker.
- How much does 1 marble cost?
- How much do 6 marbles cost?
- How much do a sticker and 6 marbles cost?
- How much do 6 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 + 1.20
Total cost of 2 marbles and 3 stickers
= 2(1 u + 1.20) + 3 u
= 2 u + 2.40 + 3 u
= 2 u + 3 u + 2.40
= 5 u + 2.40
5 u + 2.40 = 16.90
5 u = 16.90 - 2.40
5 u = 14.50
1 u = 14.50 ÷ 5 = 2.90
Cost of 1 marble
= 1 u + 1.20
= 2.90 + 1.20
= $4.10
(b)
Cost of 6 marbles
= 6 x 4.10
= $24.60
(c)
Cost of 1 sticker and 6 marbles
= 2.90 + 24.60
= $27.50
(d)
Cost of 6 marbles more than 1 sticker
= 24.60 - 2.90
= $21.70
Answer(s): (a) $4.10; (b) $24.60; (c) $27.50; (d) $21.70