If Adam buys 2 stickers and 3 marbles, it costs $31.10.
If Adam buys 3 stickers and 2 marbles, he will have $4.70 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 = 31.10 --- (1)
3 stickers + 2 marbles = 31.10 - 4.70 = 26.40 --- (2)
(1) + (2)
5 stickers + 5 marbles = 57.50 --- (3)
(3)
÷ 5 1 sticker + 1 marble = 57.50 ÷ 5 = 11.50 --- (4)
Cost of 1 sticker and 1 marble = $11.50
(b)
(4)
x 2 2 stickers + 2 marbles = 2 x 11.50 = 230 --- (5)
(2) - (5)
3 stickers + 2 marbles - 2 stickers - 2 marbles = 26.40 - 230
3 stickers - 2 stickers - 2 marbles + 2 marbles = 3.40
1 sticker = 3.40
Cost of 1 sticker = $3.40
(c)
Substitute 1 sticker = 3.40 into (4).
1 sticker + 1 marble = 11.50
3.40 + 1 marble = 11.50
1 marble = 11.50 - 3.40 = 8.10
Cost of 1 marble = $8.10
Answer(s): (a) $11.50; (b) $3.40; (c) $8.10