If Adam buys 5 stickers and 6 marbles, it costs $83.30.
If Adam buys 6 stickers and 5 marbles, he will have $3.80 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 = 83.30 --- (1)
6 stickers + 5 marbles = 83.30 - 3.80 = 79.50 --- (2)
(1) + (2)
11 stickers + 11 marbles = 162.80 --- (3)
(3)
÷ 11 1 sticker + 1 marble = 162.80 ÷ 11 = 14.80 --- (4)
Cost of 1 sticker and 1 marble = $14.80
(b)
(4)
x 5 5 stickers + 5 marbles = 5 x 14.80 = 740 --- (5)
(2) - (5)
6 stickers + 5 marbles - 5 stickers - 5 marbles = 79.50 - 740
6 stickers - 5 stickers - 5 marbles + 5 marbles = 5.50
1 sticker = 5.50
Cost of 1 sticker = $5.50
(c)
Substitute 1 sticker = 5.50 into (4).
1 sticker + 1 marble = 14.80
5.50 + 1 marble = 14.80
1 marble = 14.80 - 5.50 = 9.30
Cost of 1 marble = $9.30
Answer(s): (a) $14.80; (b) $5.50; (c) $9.30