If Adam buys 5 stickers and 6 marbles, it costs $52.40.
If Adam buys 6 stickers and 5 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)
5 stickers + 6 marbles = 52.40 --- (1)
6 stickers + 5 marbles = 52.40 - 4.70 = 47.70 --- (2)
(1) + (2)
11 stickers + 11 marbles = 100.10 --- (3)
(3)
÷ 11 1 sticker + 1 marble = 100.10 ÷ 11 = 9.10 --- (4)
Cost of 1 sticker and 1 marble = $9.10
(b)
(4)
x 5 5 stickers + 5 marbles = 5 x 9.10 = 45.50 --- (5)
(2) - (5)
6 stickers + 5 marbles - 5 stickers - 5 marbles = 47.70 - 45.50
6 stickers - 5 stickers - 5 marbles + 5 marbles = 2.20
1 sticker = 2.20
Cost of 1 sticker = $2.20
(c)
Substitute 1 sticker = 2.20 into (4).
1 sticker + 1 marble = 9.10
2.20 + 1 marble = 9.10
1 marble = 9.10 - 2.20 = 6.90
Cost of 1 marble = $6.90
Answer(s): (a) $9.10; (b) $2.20; (c) $6.90