If Adam buys 2 beads and 3 marbles, it costs $22.80.
If Adam buys 3 beads and 2 marbles, he will need another $2.90.
- 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 = 22.80 --- (1)
3 beads + 2 marbles = 22.80 + 2.90 = 25.70 --- (2)
(1) + (2)
5 beads + 5 marbles = 48.50 --- (3)
(3)
÷ 5 1 bead + 1 marble = 48.50 ÷ 5 = 9.70 --- (4)
Cost of 1 bead and 1 marble = $9.70
(b)
3 beads + 2 marbles = 25.70 --- (2)
(4)
x 2 2 beads + 2 marbles = 2 x 9.70 = 19.40 --- (5)
(2) - (5)
3 beads + 2 marbles - 2 beads - 2 marbles = 25.70 - 19.40
3 beads - 2 beads + 2 marbles - 2 marbles = 6.30
1 bead = 6.30
Cost of 1 bead = $6.30
(c)
Substitute 1 bead = 6.30 into (4).
1 bead + 1 marble = 9.70
6.30 + 1 marble = 9.70
1 marble = 9.70 - 6.30 = 3.40
Cost of 1 marble = $3.40
Answer(s): (a) $9.70; (b) $6.30; (c) $3.40