If Adam buys 4 beads and 5 marbles, it costs $50.10.
If Adam buys 5 beads and 4 marbles, he will need another $5.10.
- 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 = 50.10 --- (1)
5 beads + 4 marbles = 50.10 + 5.10 = 55.20 --- (2)
(1) + (2)
9 beads + 9 marbles = 105.30 --- (3)
(3)
÷ 9 1 bead + 1 marble = 105.30 ÷ 9 = 11.70 --- (4)
Cost of 1 bead and 1 marble = $11.70
(b)
5 beads + 4 marbles = 55.20 --- (2)
(4)
x 4 4 beads + 4 marbles = 4 x 11.70 = 46.80 --- (5)
(2) - (5)
5 beads + 4 marbles - 4 beads - 4 marbles = 55.20 - 46.80
5 beads - 4 beads + 4 marbles - 4 marbles = 8.40
1 bead = 8.40
Cost of 1 bead = $8.40
(c)
Substitute 1 bead = 8.40 into (4).
1 bead + 1 marble = 11.70
8.40 + 1 marble = 11.70
1 marble = 11.70 - 8.40 = 3.30
Cost of 1 marble = $3.30
Answer(s): (a) $11.70; (b) $8.40; (c) $3.30