If Adam buys 2 stickers and 3 marbles, it costs $29.50.
If Adam buys 3 stickers and 2 marbles, he will need another $0.50.
- Find the cost of 1 sticker and 1 marble.
- Find the cost of 1 sticker.
- Find the cost of 1 marble.
(a)
2 stickers + 3 marbles = 29.50 --- (1)
3 stickers + 2 marbles = 29.50 + 0.50 = 300 --- (2)
(1) + (2)
5 stickers + 5 marbles = 59.50 --- (3)
(3)
÷ 5 1 sticker + 1 marble = 59.50 ÷ 5 = 11.90 --- (4)
Cost of 1 sticker and 1 marble = $11.90
(b)
3 stickers + 2 marbles = 300 --- (2)
(4)
x 2 2 stickers + 2 marbles = 2 x 11.90 = 23.80 --- (5)
(2) - (5)
3 stickers + 2 marbles - 2 stickers - 2 marbles = 300 - 23.80
3 stickers - 2 stickers + 2 marbles - 2 marbles = 6.20
1 sticker = 6.20
Cost of 1 sticker = $6.20
(c)
Substitute 1 sticker = 6.20 into (4).
1 sticker + 1 marble = 11.90
6.20 + 1 marble = 11.90
1 marble = 11.90 - 6.20 = 5.70
Cost of 1 marble = $5.70
Answer(s): (a) $11.90; (b) $6.20; (c) $5.70