If Adam buys 2 marbles and 3 stickers, it costs $33.20.
If Adam buys 3 marbles and 2 stickers, he will have $3.90 left.
- 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 = 33.20 --- (1)
3 marbles + 2 stickers = 33.20 - 3.90 = 29.30 --- (2)
(1) + (2)
5 marbles + 5 stickers = 62.50 --- (3)
(3)
÷ 5 1 marble + 1 sticker = 62.50 ÷ 5 = 12.50 --- (4)
Cost of 1 marble and 1 sticker = $12.50
(b)
(4)
x 2 2 marbles + 2 stickers = 2 x 12.50 = 250 --- (5)
(2) - (5)
3 marbles + 2 stickers - 2 marbles - 2 stickers = 29.30 - 250
3 marbles - 2 marbles - 2 stickers + 2 stickers = 4.30
1 marble = 4.30
Cost of 1 marble = $4.30
(c)
Substitute 1 marble = 4.30 into (4).
1 marble + 1 sticker = 12.50
4.30 + 1 sticker = 12.50
1 sticker = 12.50 - 4.30 = 8.20
Cost of 1 sticker = $8.20
Answer(s): (a) $12.50; (b) $4.30; (c) $8.20