If Adam buys 4 marbles and 5 beads, it costs $56.10.
If Adam buys 5 marbles and 4 beads, he will have $60 left.
- Find the cost of 1 marble and 1 bead.
- Find the cost of 1 marble.
- Find the cost of 1 bead.
(a)
4 marbles + 5 beads = 56.10 --- (1)
5 marbles + 4 beads = 56.10 - 60 = 50.10 --- (2)
(1) + (2)
9 marbles + 9 beads = 106.20 --- (3)
(3)
÷ 9 1 marble + 1 bead = 106.20 ÷ 9 = 11.80 --- (4)
Cost of 1 marble and 1 bead = $11.80
(b)
(4)
x 4 4 marbles + 4 beads = 4 x 11.80 = 47.20 --- (5)
(2) - (5)
5 marbles + 4 beads - 4 marbles - 4 beads = 50.10 - 47.20
5 marbles - 4 marbles - 4 beads + 4 beads = 2.90
1 marble = 2.90
Cost of 1 marble = $2.90
(c)
Substitute 1 marble = 2.90 into (4).
1 marble + 1 bead = 11.80
2.90 + 1 bead = 11.80
1 bead = 11.80 - 2.90 = 8.90
Cost of 1 bead = $8.90
Answer(s): (a) $11.80; (b) $2.90; (c) $8.90