If Adam buys 5 stickers and 6 marbles, it costs $65.20.
If Adam buys 6 stickers and 5 marbles, he will have $6.10 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 = 65.20 --- (1)
6 stickers + 5 marbles = 65.20 - 6.10 = 59.10 --- (2)
(1) + (2)
11 stickers + 11 marbles = 124.30 --- (3)
(3)
÷ 11 1 sticker + 1 marble = 124.30 ÷ 11 = 11.30 --- (4)
Cost of 1 sticker and 1 marble = $11.30
(b)
(4)
x 5 5 stickers + 5 marbles = 5 x 11.30 = 56.50 --- (5)
(2) - (5)
6 stickers + 5 marbles - 5 stickers - 5 marbles = 59.10 - 56.50
6 stickers - 5 stickers - 5 marbles + 5 marbles = 2.60
1 sticker = 2.60
Cost of 1 sticker = $2.60
(c)
Substitute 1 sticker = 2.60 into (4).
1 sticker + 1 marble = 11.30
2.60 + 1 marble = 11.30
1 marble = 11.30 - 2.60 = 8.70
Cost of 1 marble = $8.70
Answer(s): (a) $11.30; (b) $2.60; (c) $8.70