If Adam buys 3 beads and 4 marbles, it costs $43.10.
If Adam buys 4 beads and 3 marbles, he will have $3.60 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 = 43.10 --- (1)
4 beads + 3 marbles = 43.10 - 3.60 = 39.50 --- (2)
(1) + (2)
7 beads + 7 marbles = 82.60 --- (3)
(3)
÷ 7 1 bead + 1 marble = 82.60 ÷ 7 = 11.80 --- (4)
Cost of 1 bead and 1 marble = $11.80
(b)
(4)
x 3 3 beads + 3 marbles = 3 x 11.80 = 35.40 --- (5)
(2) - (5)
4 beads + 3 marbles - 3 beads - 3 marbles = 39.50 - 35.40
4 beads - 3 beads - 3 marbles + 3 marbles = 4.10
1 bead = 4.10
Cost of 1 bead = $4.10
(c)
Substitute 1 bead = 4.10 into (4).
1 bead + 1 marble = 11.80
4.10 + 1 marble = 11.80
1 marble = 11.80 - 4.10 = 7.70
Cost of 1 marble = $7.70
Answer(s): (a) $11.80; (b) $4.10; (c) $7.70