If Adam buys 4 marbles and 5 beads, it costs $45.50.
If Adam buys 5 marbles and 4 beads, he will need another $2.60.
- Find the cost of 1 marble and 1 bead.
- Find the cost of 1 marble.
- Find the cost of 1 bead.
(a)
4 marbles + 5 beads = 45.50 --- (1)
5 marbles + 4 beads = 45.50 + 2.60 = 48.10 --- (2)
(1) + (2)
9 marbles + 9 beads = 93.60 --- (3)
(3)
÷ 9 1 marble + 1 bead = 93.60 ÷ 9 = 10.40 --- (4)
Cost of 1 marble and 1 bead = $10.40
(b)
5 marbles + 4 beads = 48.10 --- (2)
(4)
x 4 4 marbles + 4 beads = 4 x 10.40 = 41.60 --- (5)
(2) - (5)
5 marbles + 4 beads - 4 marbles - 4 beads = 48.10 - 41.60
5 marbles - 4 marbles + 4 beads - 4 beads = 6.50
1 marble = 6.50
Cost of 1 marble = $6.50
(c)
Substitute 1 marble = 6.50 into (4).
1 marble + 1 bead = 10.40
6.50 + 1 bead = 10.40
1 bead = 10.40 - 6.50 = 3.90
Cost of 1 bead = $3.90
Answer(s): (a) $10.40; (b) $6.50; (c) $3.90