If Adam buys 2 stickers and 3 marbles, it costs $37.80.
If Adam buys 3 stickers and 2 marbles, he will have $4.10 left.
- 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 = 37.80 --- (1)
3 stickers + 2 marbles = 37.80 - 4.10 = 33.70 --- (2)
(1) + (2)
5 stickers + 5 marbles = 71.50 --- (3)
(3)
÷ 5 1 sticker + 1 marble = 71.50 ÷ 5 = 14.30 --- (4)
Cost of 1 sticker and 1 marble = $14.30
(b)
(4)
x 2 2 stickers + 2 marbles = 2 x 14.30 = 28.60 --- (5)
(2) - (5)
3 stickers + 2 marbles - 2 stickers - 2 marbles = 33.70 - 28.60
3 stickers - 2 stickers - 2 marbles + 2 marbles = 5.10
1 sticker = 5.10
Cost of 1 sticker = $5.10
(c)
Substitute 1 sticker = 5.10 into (4).
1 sticker + 1 marble = 14.30
5.10 + 1 marble = 14.30
1 marble = 14.30 - 5.10 = 9.20
Cost of 1 marble = $9.20
Answer(s): (a) $14.30; (b) $5.10; (c) $9.20