If Adam buys 5 beads and 6 marbles, it costs $76.90.
If Adam buys 6 beads and 5 marbles, he will have $3.10 left.
- Find the cost of 1 bead and 1 marble.
- Find the cost of 1 bead.
- Find the cost of 1 marble.
(a)
5 beads + 6 marbles = 76.90 --- (1)
6 beads + 5 marbles = 76.90 - 3.10 = 73.80 --- (2)
(1) + (2)
11 beads + 11 marbles = 150.70 --- (3)
(3)
÷ 11 1 bead + 1 marble = 150.70 ÷ 11 = 13.70 --- (4)
Cost of 1 bead and 1 marble = $13.70
(b)
(4)
x 5 5 beads + 5 marbles = 5 x 13.70 = 68.50 --- (5)
(2) - (5)
6 beads + 5 marbles - 5 beads - 5 marbles = 73.80 - 68.50
6 beads - 5 beads - 5 marbles + 5 marbles = 5.30
1 bead = 5.30
Cost of 1 bead = $5.30
(c)
Substitute 1 bead = 5.30 into (4).
1 bead + 1 marble = 13.70
5.30 + 1 marble = 13.70
1 marble = 13.70 - 5.30 = 8.40
Cost of 1 marble = $8.40
Answer(s): (a) $13.70; (b) $5.30; (c) $8.40