If Adam buys 4 marbles and 5 beads, it costs $44.30.
If Adam buys 5 marbles and 4 beads, he will need another $2.30.
- 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 = 44.30 --- (1)
5 marbles + 4 beads = 44.30 + 2.30 = 46.60 --- (2)
(1) + (2)
9 marbles + 9 beads = 90.90 --- (3)
(3)
÷ 9 1 marble + 1 bead = 90.90 ÷ 9 = 10.10 --- (4)
Cost of 1 marble and 1 bead = $10.10
(b)
5 marbles + 4 beads = 46.60 --- (2)
(4)
x 4 4 marbles + 4 beads = 4 x 10.10 = 40.40 --- (5)
(2) - (5)
5 marbles + 4 beads - 4 marbles - 4 beads = 46.60 - 40.40
5 marbles - 4 marbles + 4 beads - 4 beads = 6.20
1 marble = 6.20
Cost of 1 marble = $6.20
(c)
Substitute 1 marble = 6.20 into (4).
1 marble + 1 bead = 10.10
6.20 + 1 bead = 10.10
1 bead = 10.10 - 6.20 = 3.90
Cost of 1 bead = $3.90
Answer(s): (a) $10.10; (b) $6.20; (c) $3.90