If Adam buys 5 marbles and 6 stickers, it costs $63.60.
If Adam buys 6 marbles and 5 stickers, he will have $40 left.
- Find the cost of 1 marble and 1 sticker.
- Find the cost of 1 marble.
- Find the cost of 1 sticker.
(a)
5 marbles + 6 stickers = 63.60 --- (1)
6 marbles + 5 stickers = 63.60 - 40 = 59.60 --- (2)
(1) + (2)
11 marbles + 11 stickers = 123.20 --- (3)
(3)
÷ 11 1 marble + 1 sticker = 123.20 ÷ 11 = 11.20 --- (4)
Cost of 1 marble and 1 sticker = $11.20
(b)
(4)
x 5 5 marbles + 5 stickers = 5 x 11.20 = 560 --- (5)
(2) - (5)
6 marbles + 5 stickers - 5 marbles - 5 stickers = 59.60 - 560
6 marbles - 5 marbles - 5 stickers + 5 stickers = 3.60
1 marble = 3.60
Cost of 1 marble = $3.60
(c)
Substitute 1 marble = 3.60 into (4).
1 marble + 1 sticker = 11.20
3.60 + 1 sticker = 11.20
1 sticker = 11.20 - 3.60 = 7.60
Cost of 1 sticker = $7.60
Answer(s): (a) $11.20; (b) $3.60; (c) $7.60