If Adam buys 3 beads and 4 marbles, it costs $50.70.
If Adam buys 4 beads and 3 marbles, he will have $4.80 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 = 50.70 --- (1)
4 beads + 3 marbles = 50.70 - 4.80 = 45.90 --- (2)
(1) + (2)
7 beads + 7 marbles = 96.60 --- (3)
(3)
÷ 7 1 bead + 1 marble = 96.60 ÷ 7 = 13.80 --- (4)
Cost of 1 bead and 1 marble = $13.80
(b)
(4)
x 3 3 beads + 3 marbles = 3 x 13.80 = 41.40 --- (5)
(2) - (5)
4 beads + 3 marbles - 3 beads - 3 marbles = 45.90 - 41.40
4 beads - 3 beads - 3 marbles + 3 marbles = 4.50
1 bead = 4.50
Cost of 1 bead = $4.50
(c)
Substitute 1 bead = 4.50 into (4).
1 bead + 1 marble = 13.80
4.50 + 1 marble = 13.80
1 marble = 13.80 - 4.50 = 9.30
Cost of 1 marble = $9.30
Answer(s): (a) $13.80; (b) $4.50; (c) $9.30