If Adam buys 4 beads and 5 marbles, it costs $61.20.
If Adam buys 5 beads and 4 marbles, he will have $4.50 left.
- 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 = 61.20 --- (1)
5 beads + 4 marbles = 61.20 - 4.50 = 56.70 --- (2)
(1) + (2)
9 beads + 9 marbles = 117.90 --- (3)
(3)
÷ 9 1 bead + 1 marble = 117.90 ÷ 9 = 13.10 --- (4)
Cost of 1 bead and 1 marble = $13.10
(b)
(4)
x 4 4 beads + 4 marbles = 4 x 13.10 = 52.40 --- (5)
(2) - (5)
5 beads + 4 marbles - 4 beads - 4 marbles = 56.70 - 52.40
5 beads - 4 beads - 4 marbles + 4 marbles = 4.30
1 bead = 4.30
Cost of 1 bead = $4.30
(c)
Substitute 1 bead = 4.30 into (4).
1 bead + 1 marble = 13.10
4.30 + 1 marble = 13.10
1 marble = 13.10 - 4.30 = 8.80
Cost of 1 marble = $8.80
Answer(s): (a) $13.10; (b) $4.30; (c) $8.80