If Adam buys 4 beads and 5 marbles, it costs $45.90.
If Adam buys 5 beads and 4 marbles, he will need another $3.60.
- Find the cost of 1 bead and 1 marble.
- Find the cost of 1 bead.
- Find the cost of 1 marble.
(a)
4 beads + 5 marbles = 45.90 --- (1)
5 beads + 4 marbles = 45.90 + 3.60 = 49.50 --- (2)
(1) + (2)
9 beads + 9 marbles = 95.40 --- (3)
(3)
÷ 9 1 bead + 1 marble = 95.40 ÷ 9 = 10.60 --- (4)
Cost of 1 bead and 1 marble = $10.60
(b)
5 beads + 4 marbles = 49.50 --- (2)
(4)
x 4 4 beads + 4 marbles = 4 x 10.60 = 42.40 --- (5)
(2) - (5)
5 beads + 4 marbles - 4 beads - 4 marbles = 49.50 - 42.40
5 beads - 4 beads + 4 marbles - 4 marbles = 7.10
1 bead = 7.10
Cost of 1 bead = $7.10
(c)
Substitute 1 bead = 7.10 into (4).
1 bead + 1 marble = 10.60
7.10 + 1 marble = 10.60
1 marble = 10.60 - 7.10 = 3.50
Cost of 1 marble = $3.50
Answer(s): (a) $10.60; (b) $7.10; (c) $3.50