If Adam buys 3 beads and 4 marbles, it costs $43.70.
If Adam buys 4 beads and 3 marbles, he will have $20 left.
- Find the cost of 1 bead and 1 marble.
- Find the cost of 1 bead.
- Find the cost of 1 marble.
(a)
3 beads + 4 marbles = 43.70 --- (1)
4 beads + 3 marbles = 43.70 - 20 = 41.70 --- (2)
(1) + (2)
7 beads + 7 marbles = 85.40 --- (3)
(3)
÷ 7 1 bead + 1 marble = 85.40 ÷ 7 = 12.20 --- (4)
Cost of 1 bead and 1 marble = $12.20
(b)
(4)
x 3 3 beads + 3 marbles = 3 x 12.20 = 36.60 --- (5)
(2) - (5)
4 beads + 3 marbles - 3 beads - 3 marbles = 41.70 - 36.60
4 beads - 3 beads - 3 marbles + 3 marbles = 5.10
1 bead = 5.10
Cost of 1 bead = $5.10
(c)
Substitute 1 bead = 5.10 into (4).
1 bead + 1 marble = 12.20
5.10 + 1 marble = 12.20
1 marble = 12.20 - 5.10 = 7.10
Cost of 1 marble = $7.10
Answer(s): (a) $12.20; (b) $5.10; (c) $7.10