If Adam buys 2 marbles and 3 stickers, it costs $34.70.
If Adam buys 3 marbles and 2 stickers, he will have $6.90 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 = 34.70 --- (1)
3 marbles + 2 stickers = 34.70 - 6.90 = 27.80 --- (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 = 27.80 - 250
3 marbles - 2 marbles - 2 stickers + 2 stickers = 2.80
1 marble = 2.80
Cost of 1 marble = $2.80
(c)
Substitute 1 marble = 2.80 into (4).
1 marble + 1 sticker = 12.50
2.80 + 1 sticker = 12.50
1 sticker = 12.50 - 2.80 = 9.70
Cost of 1 sticker = $9.70
Answer(s): (a) $12.50; (b) $2.80; (c) $9.70