If Adam buys 2 marbles and 3 stickers, it costs $31.60.
If Adam buys 3 marbles and 2 stickers, he will have $3.70 left.
- 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 = 31.60 --- (1)
3 marbles + 2 stickers = 31.60 - 3.70 = 27.90 --- (2)
(1) + (2)
5 marbles + 5 stickers = 59.50 --- (3)
(3)
÷ 5 1 marble + 1 sticker = 59.50 ÷ 5 = 11.90 --- (4)
Cost of 1 marble and 1 sticker = $11.90
(b)
(4)
x 2 2 marbles + 2 stickers = 2 x 11.90 = 23.80 --- (5)
(2) - (5)
3 marbles + 2 stickers - 2 marbles - 2 stickers = 27.90 - 23.80
3 marbles - 2 marbles - 2 stickers + 2 stickers = 4.10
1 marble = 4.10
Cost of 1 marble = $4.10
(c)
Substitute 1 marble = 4.10 into (4).
1 marble + 1 sticker = 11.90
4.10 + 1 sticker = 11.90
1 sticker = 11.90 - 4.10 = 7.80
Cost of 1 sticker = $7.80
Answer(s): (a) $11.90; (b) $4.10; (c) $7.80