If Adam buys 3 beads and 4 marbles, it costs $42.40.
If Adam buys 4 beads and 3 marbles, he will have $1.50 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 = 42.40 --- (1)
4 beads + 3 marbles = 42.40 - 1.50 = 40.90 --- (2)
(1) + (2)
7 beads + 7 marbles = 83.30 --- (3)
(3)
÷ 7 1 bead + 1 marble = 83.30 ÷ 7 = 11.90 --- (4)
Cost of 1 bead and 1 marble = $11.90
(b)
(4)
x 3 3 beads + 3 marbles = 3 x 11.90 = 35.70 --- (5)
(2) - (5)
4 beads + 3 marbles - 3 beads - 3 marbles = 40.90 - 35.70
4 beads - 3 beads - 3 marbles + 3 marbles = 5.20
1 bead = 5.20
Cost of 1 bead = $5.20
(c)
Substitute 1 bead = 5.20 into (4).
1 bead + 1 marble = 11.90
5.20 + 1 marble = 11.90
1 marble = 11.90 - 5.20 = 6.70
Cost of 1 marble = $6.70
Answer(s): (a) $11.90; (b) $5.20; (c) $6.70