If Adam buys 2 marbles and 3 stickers, it costs $25.70.
If Adam buys 3 marbles and 2 stickers, he will need another $5.10.
- 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 = 25.70 --- (1)
3 marbles + 2 stickers = 25.70 + 5.10 = 30.80 --- (2)
(1) + (2)
5 marbles + 5 stickers = 56.50 --- (3)
(3)
÷ 5 1 marble + 1 sticker = 56.50 ÷ 5 = 11.30 --- (4)
Cost of 1 marble and 1 sticker = $11.30
(b)
3 marbles + 2 stickers = 30.80 --- (2)
(4)
x 2 2 marbles + 2 stickers = 2 x 11.30 = 22.60 --- (5)
(2) - (5)
3 marbles + 2 stickers - 2 marbles - 2 stickers = 30.80 - 22.60
3 marbles - 2 marbles + 2 stickers - 2 stickers = 8.20
1 marble = 8.20
Cost of 1 marble = $8.20
(c)
Substitute 1 marble = 8.20 into (4).
1 marble + 1 sticker = 11.30
8.20 + 1 sticker = 11.30
1 sticker = 11.30 - 8.20 = 3.10
Cost of 1 sticker = $3.10
Answer(s): (a) $11.30; (b) $8.20; (c) $3.10