If Adam buys 4 beads and 5 marbles, it costs $59.10.
If Adam buys 5 beads and 4 marbles, he will have $5.70 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 = 59.10 --- (1)
5 beads + 4 marbles = 59.10 - 5.70 = 53.40 --- (2)
(1) + (2)
9 beads + 9 marbles = 112.50 --- (3)
(3)
÷ 9 1 bead + 1 marble = 112.50 ÷ 9 = 12.50 --- (4)
Cost of 1 bead and 1 marble = $12.50
(b)
(4)
x 4 4 beads + 4 marbles = 4 x 12.50 = 500 --- (5)
(2) - (5)
5 beads + 4 marbles - 4 beads - 4 marbles = 53.40 - 500
5 beads - 4 beads - 4 marbles + 4 marbles = 3.40
1 bead = 3.40
Cost of 1 bead = $3.40
(c)
Substitute 1 bead = 3.40 into (4).
1 bead + 1 marble = 12.50
3.40 + 1 marble = 12.50
1 marble = 12.50 - 3.40 = 9.10
Cost of 1 marble = $9.10
Answer(s): (a) $12.50; (b) $3.40; (c) $9.10