Adam spends $15.10 on 5 marbles and 6 stickers.
A marble costs $1.70 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 + 1.70
Total cost of 5 marbles and 6 stickers
= 5(1 u + 1.70) + 6 u
= 5 u + 8.50 + 6 u
= 5 u + 6 u + 8.50
= 11 u + 8.50
11 u + 8.50 = 15.10
11 u = 15.10 - 8.50
11 u = 6.60
1 u = 6.60 ÷ 11 = 0.60
Cost of 1 marble
= 1 u + 1.70
= 0.60 + 1.70
= $2.30
(b)
Cost of 6 marbles
= 6 x 2.30
= $13.80
(c)
Cost of 1 sticker and 6 marbles
= 0.60 + 13.80
= $14.40
(d)
Cost of 6 marbles more than 1 sticker
= 13.80 - 0.60
= $13.20
Answer(s): (a) $2.30; (b) $13.80; (c) $14.40; (d) $13.20