Adam spends $14.10 on 3 marbles and 4 stickers.
A marble costs $1.90 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 + 1.90
Total cost of 3 marbles and 4 stickers
= 3(1 u + 1.90) + 4 u
= 3 u + 5.70 + 4 u
= 3 u + 4 u + 5.70
= 7 u + 5.70
7 u + 5.70 = 14.10
7 u = 14.10 - 5.70
7 u = 8.40
1 u = 8.40 ÷ 7 = 1.20
Cost of 1 marble
= 1 u + 1.90
= 1.20 + 1.90
= $3.10
(b)
Cost of 5 marbles
= 5 x 3.10
= $15.50
(c)
Cost of 1 sticker and 5 marbles
= 1.20 + 15.50
= $16.70
(d)
Cost of 5 marbles more than 1 sticker
= 15.50 - 1.20
= $14.30
Answer(s): (a) $3.10; (b) $15.50; (c) $16.70; (d) $14.30