If Adam buys 2 marbles and 3 stickers, it costs $300.
If Adam buys 3 marbles and 2 stickers, he will need another $0.50.
- Find the cost of 1 marble and 1 sticker.
- Find the cost of 1 marble.
- Find the cost of 1 sticker.
(a)
2 marbles + 3 stickers = 300 --- (1)
3 marbles + 2 stickers = 300 + 0.50 = 30.50 --- (2)
(1) + (2)
5 marbles + 5 stickers = 60.50 --- (3)
(3)
÷ 5 1 marble + 1 sticker = 60.50 ÷ 5 = 12.10 --- (4)
Cost of 1 marble and 1 sticker = $12.10
(b)
3 marbles + 2 stickers = 30.50 --- (2)
(4)
x 2 2 marbles + 2 stickers = 2 x 12.10 = 24.20 --- (5)
(2) - (5)
3 marbles + 2 stickers - 2 marbles - 2 stickers = 30.50 - 24.20
3 marbles - 2 marbles + 2 stickers - 2 stickers = 6.30
1 marble = 6.30
Cost of 1 marble = $6.30
(c)
Substitute 1 marble = 6.30 into (4).
1 marble + 1 sticker = 12.10
6.30 + 1 sticker = 12.10
1 sticker = 12.10 - 6.30 = 5.80
Cost of 1 sticker = $5.80
Answer(s): (a) $12.10; (b) $6.30; (c) $5.80