If Adam buys 5 marbles and 6 beads, it costs $45.60.
If Adam buys 6 marbles and 5 beads, he will have $5.40 left.
- Find the cost of 1 marble and 1 bead.
- Find the cost of 1 marble.
- Find the cost of 1 bead.
(a)
5 marbles + 6 beads = 45.60 --- (1)
6 marbles + 5 beads = 45.60 - 5.40 = 40.20 --- (2)
(1) + (2)
11 marbles + 11 beads = 85.80 --- (3)
(3)
÷ 11 1 marble + 1 bead = 85.80 ÷ 11 = 7.80 --- (4)
Cost of 1 marble and 1 bead = $7.80
(b)
(4)
x 5 5 marbles + 5 beads = 5 x 7.80 = 390 --- (5)
(2) - (5)
6 marbles + 5 beads - 5 marbles - 5 beads = 40.20 - 390
6 marbles - 5 marbles - 5 beads + 5 beads = 1.20
1 marble = 1.20
Cost of 1 marble = $1.20
(c)
Substitute 1 marble = 1.20 into (4).
1 marble + 1 bead = 7.80
1.20 + 1 bead = 7.80
1 bead = 7.80 - 1.20 = 6.60
Cost of 1 bead = $6.60
Answer(s): (a) $7.80; (b) $1.20; (c) $6.60