If Adam buys 4 stickers and 5 marbles, it costs $49.10.
If Adam buys 5 stickers and 4 marbles, he will have $5.50 left.
- Find the cost of 1 sticker and 1 marble.
- Find the cost of 1 sticker.
- Find the cost of 1 marble.
(a)
4 stickers + 5 marbles = 49.10 --- (1)
5 stickers + 4 marbles = 49.10 - 5.50 = 43.60 --- (2)
(1) + (2)
9 stickers + 9 marbles = 92.70 --- (3)
(3)
÷ 9 1 sticker + 1 marble = 92.70 ÷ 9 = 10.30 --- (4)
Cost of 1 sticker and 1 marble = $10.30
(b)
(4)
x 4 4 stickers + 4 marbles = 4 x 10.30 = 41.20 --- (5)
(2) - (5)
5 stickers + 4 marbles - 4 stickers - 4 marbles = 43.60 - 41.20
5 stickers - 4 stickers - 4 marbles + 4 marbles = 2.40
1 sticker = 2.40
Cost of 1 sticker = $2.40
(c)
Substitute 1 sticker = 2.40 into (4).
1 sticker + 1 marble = 10.30
2.40 + 1 marble = 10.30
1 marble = 10.30 - 2.40 = 7.90
Cost of 1 marble = $7.90
Answer(s): (a) $10.30; (b) $2.40; (c) $7.90