If Adam buys 2 beads and 3 marbles, it costs $280.
If Adam buys 3 beads and 2 marbles, he will need another $4.50.
- Find the cost of 1 bead and 1 marble.
- Find the cost of 1 bead.
- Find the cost of 1 marble.
(a)
2 beads + 3 marbles = 280 --- (1)
3 beads + 2 marbles = 280 + 4.50 = 32.50 --- (2)
(1) + (2)
5 beads + 5 marbles = 60.50 --- (3)
(3)
÷ 5 1 bead + 1 marble = 60.50 ÷ 5 = 12.10 --- (4)
Cost of 1 bead and 1 marble = $12.10
(b)
3 beads + 2 marbles = 32.50 --- (2)
(4)
x 2 2 beads + 2 marbles = 2 x 12.10 = 24.20 --- (5)
(2) - (5)
3 beads + 2 marbles - 2 beads - 2 marbles = 32.50 - 24.20
3 beads - 2 beads + 2 marbles - 2 marbles = 8.30
1 bead = 8.30
Cost of 1 bead = $8.30
(c)
Substitute 1 bead = 8.30 into (4).
1 bead + 1 marble = 12.10
8.30 + 1 marble = 12.10
1 marble = 12.10 - 8.30 = 3.80
Cost of 1 marble = $3.80
Answer(s): (a) $12.10; (b) $8.30; (c) $3.80