If Adam buys 5 stickers and 6 marbles, it costs $83.80.
If Adam buys 6 stickers and 5 marbles, he will have $3.70 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 = 83.80 --- (1)
6 stickers + 5 marbles = 83.80 - 3.70 = 80.10 --- (2)
(1) + (2)
11 stickers + 11 marbles = 163.90 --- (3)
(3)
÷ 11 1 sticker + 1 marble = 163.90 ÷ 11 = 14.90 --- (4)
Cost of 1 sticker and 1 marble = $14.90
(b)
(4)
x 5 5 stickers + 5 marbles = 5 x 14.90 = 74.50 --- (5)
(2) - (5)
6 stickers + 5 marbles - 5 stickers - 5 marbles = 80.10 - 74.50
6 stickers - 5 stickers - 5 marbles + 5 marbles = 5.60
1 sticker = 5.60
Cost of 1 sticker = $5.60
(c)
Substitute 1 sticker = 5.60 into (4).
1 sticker + 1 marble = 14.90
5.60 + 1 marble = 14.90
1 marble = 14.90 - 5.60 = 9.30
Cost of 1 marble = $9.30
Answer(s): (a) $14.90; (b) $5.60; (c) $9.30