If Adam buys 4 marbles and 5 stickers, it costs $53.60.
If Adam buys 5 marbles and 4 stickers, he will need another $2.60.
- Find the cost of 1 marble and 1 sticker.
- Find the cost of 1 marble.
- Find the cost of 1 sticker.
(a)
4 marbles + 5 stickers = 53.60 --- (1)
5 marbles + 4 stickers = 53.60 + 2.60 = 56.20 --- (2)
(1) + (2)
9 marbles + 9 stickers = 109.80 --- (3)
(3)
÷ 9 1 marble + 1 sticker = 109.80 ÷ 9 = 12.20 --- (4)
Cost of 1 marble and 1 sticker = $12.20
(b)
5 marbles + 4 stickers = 56.20 --- (2)
(4)
x 4 4 marbles + 4 stickers = 4 x 12.20 = 48.80 --- (5)
(2) - (5)
5 marbles + 4 stickers - 4 marbles - 4 stickers = 56.20 - 48.80
5 marbles - 4 marbles + 4 stickers - 4 stickers = 7.40
1 marble = 7.40
Cost of 1 marble = $7.40
(c)
Substitute 1 marble = 7.40 into (4).
1 marble + 1 sticker = 12.20
7.40 + 1 sticker = 12.20
1 sticker = 12.20 - 7.40 = 4.80
Cost of 1 sticker = $4.80
Answer(s): (a) $12.20; (b) $7.40; (c) $4.80