If Adam buys 4 marbles and 5 stickers, it costs $45.10.
If Adam buys 5 marbles and 4 stickers, he will need another $2.50.
- Find the cost of 1 marble and 1 sticker.
- Find the cost of 1 marble.
- Find the cost of 1 sticker.
(a)
4 marbles + 5 stickers = 45.10 --- (1)
5 marbles + 4 stickers = 45.10 + 2.50 = 47.60 --- (2)
(1) + (2)
9 marbles + 9 stickers = 92.70 --- (3)
(3)
÷ 9 1 marble + 1 sticker = 92.70 ÷ 9 = 10.30 --- (4)
Cost of 1 marble and 1 sticker = $10.30
(b)
5 marbles + 4 stickers = 47.60 --- (2)
(4)
x 4 4 marbles + 4 stickers = 4 x 10.30 = 41.20 --- (5)
(2) - (5)
5 marbles + 4 stickers - 4 marbles - 4 stickers = 47.60 - 41.20
5 marbles - 4 marbles + 4 stickers - 4 stickers = 6.40
1 marble = 6.40
Cost of 1 marble = $6.40
(c)
Substitute 1 marble = 6.40 into (4).
1 marble + 1 sticker = 10.30
6.40 + 1 sticker = 10.30
1 sticker = 10.30 - 6.40 = 3.90
Cost of 1 sticker = $3.90
Answer(s): (a) $10.30; (b) $6.40; (c) $3.90