If Adam buys 2 marbles and 3 beads, it costs $29.60.
If Adam buys 3 marbles and 2 beads, he will need another $4.30.
- Find the cost of 1 marble and 1 bead.
- Find the cost of 1 marble.
- Find the cost of 1 bead.
(a)
2 marbles + 3 beads = 29.60 --- (1)
3 marbles + 2 beads = 29.60 + 4.30 = 33.90 --- (2)
(1) + (2)
5 marbles + 5 beads = 63.50 --- (3)
(3)
÷ 5 1 marble + 1 bead = 63.50 ÷ 5 = 12.70 --- (4)
Cost of 1 marble and 1 bead = $12.70
(b)
3 marbles + 2 beads = 33.90 --- (2)
(4)
x 2 2 marbles + 2 beads = 2 x 12.70 = 25.40 --- (5)
(2) - (5)
3 marbles + 2 beads - 2 marbles - 2 beads = 33.90 - 25.40
3 marbles - 2 marbles + 2 beads - 2 beads = 8.50
1 marble = 8.50
Cost of 1 marble = $8.50
(c)
Substitute 1 marble = 8.50 into (4).
1 marble + 1 bead = 12.70
8.50 + 1 bead = 12.70
1 bead = 12.70 - 8.50 = 4.20
Cost of 1 bead = $4.20
Answer(s): (a) $12.70; (b) $8.50; (c) $4.20