Adam spends $16.30 on 2 marbles and 3 stickers.
A marble costs $1.40 more than 1 sticker.
- How much does 1 marble cost?
- How much do 4 marbles cost?
- How much do a sticker and 4 marbles cost?
- How much do 4 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 + 1.40
Total cost of 2 marbles and 3 stickers
= 2(1 u + 1.40) + 3 u
= 2 u + 2.80 + 3 u
= 2 u + 3 u + 2.80
= 5 u + 2.80
5 u + 2.80 = 16.30
5 u = 16.30 - 2.80
5 u = 13.50
1 u = 13.50 ÷ 5 = 2.70
Cost of 1 marble
= 1 u + 1.40
= 2.70 + 1.40
= $4.10
(b)
Cost of 4 marbles
= 4 x 4.10
= $16.40
(c)
Cost of 1 sticker and 4 marbles
= 2.70 + 16.40
= $19.10
(d)
Cost of 4 marbles more than 1 sticker
= 16.40 - 2.70
= $13.70
Answer(s): (a) $4.10; (b) $16.40; (c) $19.10; (d) $13.70