If Adam buys 2 beads and 3 marbles, it costs $27.90.
If Adam buys 3 beads and 2 marbles, he will need another $2.70.
- 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 = 27.90 --- (1)
3 beads + 2 marbles = 27.90 + 2.70 = 30.60 --- (2)
(1) + (2)
5 beads + 5 marbles = 58.50 --- (3)
(3)
÷ 5 1 bead + 1 marble = 58.50 ÷ 5 = 11.70 --- (4)
Cost of 1 bead and 1 marble = $11.70
(b)
3 beads + 2 marbles = 30.60 --- (2)
(4)
x 2 2 beads + 2 marbles = 2 x 11.70 = 23.40 --- (5)
(2) - (5)
3 beads + 2 marbles - 2 beads - 2 marbles = 30.60 - 23.40
3 beads - 2 beads + 2 marbles - 2 marbles = 7.20
1 bead = 7.20
Cost of 1 bead = $7.20
(c)
Substitute 1 bead = 7.20 into (4).
1 bead + 1 marble = 11.70
7.20 + 1 marble = 11.70
1 marble = 11.70 - 7.20 = 4.50
Cost of 1 marble = $4.50
Answer(s): (a) $11.70; (b) $7.20; (c) $4.50