If Adam buys 3 beads and 4 marbles, it costs $50.90.
If Adam buys 4 beads and 3 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)
3 beads + 4 marbles = 50.90 --- (1)
4 beads + 3 marbles = 50.90 - 3.10 = 47.80 --- (2)
(1) + (2)
7 beads + 7 marbles = 98.70 --- (3)
(3)
÷ 7 1 bead + 1 marble = 98.70 ÷ 7 = 14.10 --- (4)
Cost of 1 bead and 1 marble = $14.10
(b)
(4)
x 3 3 beads + 3 marbles = 3 x 14.10 = 42.30 --- (5)
(2) - (5)
4 beads + 3 marbles - 3 beads - 3 marbles = 47.80 - 42.30
4 beads - 3 beads - 3 marbles + 3 marbles = 5.50
1 bead = 5.50
Cost of 1 bead = $5.50
(c)
Substitute 1 bead = 5.50 into (4).
1 bead + 1 marble = 14.10
5.50 + 1 marble = 14.10
1 marble = 14.10 - 5.50 = 8.60
Cost of 1 marble = $8.60
Answer(s): (a) $14.10; (b) $5.50; (c) $8.60