If Adam buys 4 beads and 5 marbles, it costs $50.10.
If Adam buys 5 beads and 4 marbles, he will need another $1.50.
- 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 + 1.50 = 51.60 --- (2)
(1) + (2)
9 beads + 9 marbles = 101.70 --- (3)
(3)
÷ 9 1 bead + 1 marble = 101.70 ÷ 9 = 11.30 --- (4)
Cost of 1 bead and 1 marble = $11.30
(b)
5 beads + 4 marbles = 51.60 --- (2)
(4)
x 4 4 beads + 4 marbles = 4 x 11.30 = 45.20 --- (5)
(2) - (5)
5 beads + 4 marbles - 4 beads - 4 marbles = 51.60 - 45.20
5 beads - 4 beads + 4 marbles - 4 marbles = 6.40
1 bead = 6.40
Cost of 1 bead = $6.40
(c)
Substitute 1 bead = 6.40 into (4).
1 bead + 1 marble = 11.30
6.40 + 1 marble = 11.30
1 marble = 11.30 - 6.40 = 4.90
Cost of 1 marble = $4.90
Answer(s): (a) $11.30; (b) $6.40; (c) $4.90