If Adam buys 5 marbles and 6 stickers, it costs $59.60.
If Adam buys 6 marbles and 5 stickers, he will have $4.80 left.
- Find the cost of 1 marble and 1 sticker.
- Find the cost of 1 marble.
- Find the cost of 1 sticker.
(a)
5 marbles + 6 stickers = 59.60 --- (1)
6 marbles + 5 stickers = 59.60 - 4.80 = 54.80 --- (2)
(1) + (2)
11 marbles + 11 stickers = 114.40 --- (3)
(3)
÷ 11 1 marble + 1 sticker = 114.40 ÷ 11 = 10.40 --- (4)
Cost of 1 marble and 1 sticker = $10.40
(b)
(4)
x 5 5 marbles + 5 stickers = 5 x 10.40 = 520 --- (5)
(2) - (5)
6 marbles + 5 stickers - 5 marbles - 5 stickers = 54.80 - 520
6 marbles - 5 marbles - 5 stickers + 5 stickers = 2.80
1 marble = 2.80
Cost of 1 marble = $2.80
(c)
Substitute 1 marble = 2.80 into (4).
1 marble + 1 sticker = 10.40
2.80 + 1 sticker = 10.40
1 sticker = 10.40 - 2.80 = 7.60
Cost of 1 sticker = $7.60
Answer(s): (a) $10.40; (b) $2.80; (c) $7.60