If Adam buys 3 beads and 4 marbles, it costs $44.30.
If Adam buys 4 beads and 3 marbles, he will have $1.80 left.

1. Find the cost of 1 bead and 1 marble.
2. Find the cost of 1 bead.
3. Find the cost of 1 marble.

(a)
3 beads + 4 marbles = 44.30 --- (1)
4 beads + 3 marbles = 44.30 - 1.80 = 42.50 --- (2)

(1) + (2)
7 beads + 7 marbles = 86.80 --- (3)

(3) _{÷ 7}
1 bead + 1 marble = 86.80 ÷ 7 = 12.40 --- (4)

Cost of 1 bead and 1 marble = $12.40

(b)
(4) _{x 3}
3 beads + 3 marbles = 3 x 12.40 = 37.20 --- (5)

(2) - (5)
4 beads + 3 marbles - 3 beads - 3 marbles = 42.50 - 37.20
4 beads - 3 beads - 3 marbles + 3 marbles = 5.30
1 bead = 5.30

Cost of 1 bead = $5.30

(c)
Substitute 1 bead = 5.30 into (4).

1 bead + 1 marble = 12.40
5.30 + 1 marble = 12.40
1 marble = 12.40 - 5.30 = 7.10

Cost of 1 marble = $7.10

Answer(s): (a) $12.40; (b) $5.30; (c) $7.10