If Adam buys 5 marbles and 6 beads, it costs $56.80.
If Adam buys 6 marbles and 5 beads, he will have $6.90 left.
- Find the cost of 1 marble and 1 bead.
- Find the cost of 1 marble.
- Find the cost of 1 bead.
(a)
5 marbles + 6 beads = 56.80 --- (1)
6 marbles + 5 beads = 56.80 - 6.90 = 49.90 --- (2)
(1) + (2)
11 marbles + 11 beads = 106.70 --- (3)
(3)
÷ 11 1 marble + 1 bead = 106.70 ÷ 11 = 9.70 --- (4)
Cost of 1 marble and 1 bead = $9.70
(b)
(4)
x 5 5 marbles + 5 beads = 5 x 9.70 = 48.50 --- (5)
(2) - (5)
6 marbles + 5 beads - 5 marbles - 5 beads = 49.90 - 48.50
6 marbles - 5 marbles - 5 beads + 5 beads = 1.40
1 marble = 1.40
Cost of 1 marble = $1.40
(c)
Substitute 1 marble = 1.40 into (4).
1 marble + 1 bead = 9.70
1.40 + 1 bead = 9.70
1 bead = 9.70 - 1.40 = 8.30
Cost of 1 bead = $8.30
Answer(s): (a) $9.70; (b) $1.40; (c) $8.30