If Adam buys 2 marbles and 3 stickers, it costs $36.20.
If Adam buys 3 marbles and 2 stickers, he will have $2.90 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 = 36.20 --- (1)
3 marbles + 2 stickers = 36.20 - 2.90 = 33.30 --- (2)
(1) + (2)
5 marbles + 5 stickers = 69.50 --- (3)
(3)
÷ 5 1 marble + 1 sticker = 69.50 ÷ 5 = 13.90 --- (4)
Cost of 1 marble and 1 sticker = $13.90
(b)
(4)
x 2 2 marbles + 2 stickers = 2 x 13.90 = 27.80 --- (5)
(2) - (5)
3 marbles + 2 stickers - 2 marbles - 2 stickers = 33.30 - 27.80
3 marbles - 2 marbles - 2 stickers + 2 stickers = 5.50
1 marble = 5.50
Cost of 1 marble = $5.50
(c)
Substitute 1 marble = 5.50 into (4).
1 marble + 1 sticker = 13.90
5.50 + 1 sticker = 13.90
1 sticker = 13.90 - 5.50 = 8.40
Cost of 1 sticker = $8.40
Answer(s): (a) $13.90; (b) $5.50; (c) $8.40