If Adam buys 2 marbles and 3 beads, it costs $27.70.
If Adam buys 3 marbles and 2 beads, he will need another $1.10.
- Find the cost of 1 marble and 1 bead.
- Find the cost of 1 marble.
- Find the cost of 1 bead.
(a)
2 marbles + 3 beads = 27.70 --- (1)
3 marbles + 2 beads = 27.70 + 1.10 = 28.80 --- (2)
(1) + (2)
5 marbles + 5 beads = 56.50 --- (3)
(3)
÷ 5 1 marble + 1 bead = 56.50 ÷ 5 = 11.30 --- (4)
Cost of 1 marble and 1 bead = $11.30
(b)
3 marbles + 2 beads = 28.80 --- (2)
(4)
x 2 2 marbles + 2 beads = 2 x 11.30 = 22.60 --- (5)
(2) - (5)
3 marbles + 2 beads - 2 marbles - 2 beads = 28.80 - 22.60
3 marbles - 2 marbles + 2 beads - 2 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 = 11.30
6.20 + 1 bead = 11.30
1 bead = 11.30 - 6.20 = 5.10
Cost of 1 bead = $5.10
Answer(s): (a) $11.30; (b) $6.20; (c) $5.10