If Adam buys 4 marbles and 5 stickers, it costs $61.60.
If Adam buys 5 marbles and 4 stickers, he will have $3.50 left.
- 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 = 61.60 --- (1)
5 marbles + 4 stickers = 61.60 - 3.50 = 58.10 --- (2)
(1) + (2)
9 marbles + 9 stickers = 119.70 --- (3)
(3)
÷ 9 1 marble + 1 sticker = 119.70 ÷ 9 = 13.30 --- (4)
Cost of 1 marble and 1 sticker = $13.30
(b)
(4)
x 4 4 marbles + 4 stickers = 4 x 13.30 = 53.20 --- (5)
(2) - (5)
5 marbles + 4 stickers - 4 marbles - 4 stickers = 58.10 - 53.20
5 marbles - 4 marbles - 4 stickers + 4 stickers = 4.90
1 marble = 4.90
Cost of 1 marble = $4.90
(c)
Substitute 1 marble = 4.90 into (4).
1 marble + 1 sticker = 13.30
4.90 + 1 sticker = 13.30
1 sticker = 13.30 - 4.90 = 8.40
Cost of 1 sticker = $8.40
Answer(s): (a) $13.30; (b) $4.90; (c) $8.40