If Adam buys 5 stickers and 6 marbles, it costs $74.60.
If Adam buys 6 stickers and 5 marbles, he will have $1.80 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 = 74.60 --- (1)
6 stickers + 5 marbles = 74.60 - 1.80 = 72.80 --- (2)
(1) + (2)
11 stickers + 11 marbles = 147.40 --- (3)
(3)
÷ 11 1 sticker + 1 marble = 147.40 ÷ 11 = 13.40 --- (4)
Cost of 1 sticker and 1 marble = $13.40
(b)
(4)
x 5 5 stickers + 5 marbles = 5 x 13.40 = 670 --- (5)
(2) - (5)
6 stickers + 5 marbles - 5 stickers - 5 marbles = 72.80 - 670
6 stickers - 5 stickers - 5 marbles + 5 marbles = 5.80
1 sticker = 5.80
Cost of 1 sticker = $5.80
(c)
Substitute 1 sticker = 5.80 into (4).
1 sticker + 1 marble = 13.40
5.80 + 1 marble = 13.40
1 marble = 13.40 - 5.80 = 7.60
Cost of 1 marble = $7.60
Answer(s): (a) $13.40; (b) $5.80; (c) $7.60