If Adam buys 5 stickers and 6 marbles, it costs $72.10.
If Adam buys 6 stickers and 5 marbles, he will have $4.50 left.
- Find the cost of 1 sticker and 1 marble.
- Find the cost of 1 sticker.
- Find the cost of 1 marble.
(a)
5 stickers + 6 marbles = 72.10 --- (1)
6 stickers + 5 marbles = 72.10 - 4.50 = 67.60 --- (2)
(1) + (2)
11 stickers + 11 marbles = 139.70 --- (3)
(3)
÷ 11 1 sticker + 1 marble = 139.70 ÷ 11 = 12.70 --- (4)
Cost of 1 sticker and 1 marble = $12.70
(b)
(4)
x 5 5 stickers + 5 marbles = 5 x 12.70 = 63.50 --- (5)
(2) - (5)
6 stickers + 5 marbles - 5 stickers - 5 marbles = 67.60 - 63.50
6 stickers - 5 stickers - 5 marbles + 5 marbles = 4.10
1 sticker = 4.10
Cost of 1 sticker = $4.10
(c)
Substitute 1 sticker = 4.10 into (4).
1 sticker + 1 marble = 12.70
4.10 + 1 marble = 12.70
1 marble = 12.70 - 4.10 = 8.60
Cost of 1 marble = $8.60
Answer(s): (a) $12.70; (b) $4.10; (c) $8.60