If Adam buys 2 stickers and 3 marbles, it costs $32.90.
If Adam buys 3 stickers and 2 marbles, he will need another $3.70.
- 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 = 32.90 --- (1)
3 stickers + 2 marbles = 32.90 + 3.70 = 36.60 --- (2)
(1) + (2)
5 stickers + 5 marbles = 69.50 --- (3)
(3)
÷ 5 1 sticker + 1 marble = 69.50 ÷ 5 = 13.90 --- (4)
Cost of 1 sticker and 1 marble = $13.90
(b)
3 stickers + 2 marbles = 36.60 --- (2)
(4)
x 2 2 stickers + 2 marbles = 2 x 13.90 = 27.80 --- (5)
(2) - (5)
3 stickers + 2 marbles - 2 stickers - 2 marbles = 36.60 - 27.80
3 stickers - 2 stickers + 2 marbles - 2 marbles = 8.80
1 sticker = 8.80
Cost of 1 sticker = $8.80
(c)
Substitute 1 sticker = 8.80 into (4).
1 sticker + 1 marble = 13.90
8.80 + 1 marble = 13.90
1 marble = 13.90 - 8.80 = 5.10
Cost of 1 marble = $5.10
Answer(s): (a) $13.90; (b) $8.80; (c) $5.10