If Adam buys 2 beads and 3 marbles, it costs $29.30.
If Adam buys 3 beads and 2 marbles, he will need another $0.90.
- 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 = 29.30 --- (1)
3 beads + 2 marbles = 29.30 + 0.90 = 30.20 --- (2)
(1) + (2)
5 beads + 5 marbles = 59.50 --- (3)
(3)
÷ 5 1 bead + 1 marble = 59.50 ÷ 5 = 11.90 --- (4)
Cost of 1 bead and 1 marble = $11.90
(b)
3 beads + 2 marbles = 30.20 --- (2)
(4)
x 2 2 beads + 2 marbles = 2 x 11.90 = 23.80 --- (5)
(2) - (5)
3 beads + 2 marbles - 2 beads - 2 marbles = 30.20 - 23.80
3 beads - 2 beads + 2 marbles - 2 marbles = 6.40
1 bead = 6.40
Cost of 1 bead = $6.40
(c)
Substitute 1 bead = 6.40 into (4).
1 bead + 1 marble = 11.90
6.40 + 1 marble = 11.90
1 marble = 11.90 - 6.40 = 5.50
Cost of 1 marble = $5.50
Answer(s): (a) $11.90; (b) $6.40; (c) $5.50