If Adam buys 2 marbles and 3 beads, it costs $22.80.
If Adam buys 3 marbles and 2 beads, he will need another $2.90.

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

(a)
2 marbles + 3 beads = 22.80 --- (1)
3 marbles + 2 beads = 22.80 + 2.90 = 25.70 --- (2)

(1) + (2)
5 marbles + 5 beads = 48.50 --- (3)

(3) _{÷ 5}
1 marble + 1 bead = 48.50 ÷ 5 = 9.70 --- (4)

Cost of 1 marble and 1 bead = $9.70

(b)
3 marbles + 2 beads = 25.70 --- (2)

(4) _{x 2}
2 marbles + 2 beads = 2 x 9.70 = 19.40 --- (5)

(2) - (5)
3 marbles + 2 beads - 2 marbles - 2 beads = 25.70 - 19.40
3 marbles - 2 marbles + 2 beads - 2 beads = 6.30
1 marble = 6.30

Cost of 1 marble = $6.30

(c)
Substitute 1 marble = 6.30 into (4).

1 marble + 1 bead = 9.70
6.30 + 1 bead = 9.70
1 bead = 9.70 - 6.30 = 3.40

Cost of 1 bead = $3.40

Answer(s): (a) $9.70; (b) $6.30; (c) $3.40