If Adam buys 4 beads and 5 marbles, it costs $64.20.
If Adam buys 5 beads and 4 marbles, he will have $3.30 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)
4 beads + 5 marbles = 64.20 --- (1)
5 beads + 4 marbles = 64.20 - 3.30 = 60.90 --- (2)

(1) + (2)
9 beads + 9 marbles = 125.10 --- (3)

(3) _{÷ 9}
1 bead + 1 marble = 125.10 ÷ 9 = 13.90 --- (4)

Cost of 1 bead and 1 marble = $13.90

(b)
(4) _{x 4}
4 beads + 4 marbles = 4 x 13.90 = 55.60 --- (5)

(2) - (5)
5 beads + 4 marbles - 4 beads - 4 marbles = 60.90 - 55.60
5 beads - 4 beads - 4 marbles + 4 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 = 13.90
5.30 + 1 marble = 13.90
1 marble = 13.90 - 5.30 = 8.60

Cost of 1 marble = $8.60

Answer(s): (a) $13.90; (b) $5.30; (c) $8.60