If Adam buys 4 marbles and 5 beads, it costs $63.10.
If Adam buys 5 marbles and 4 beads, he will have $6.50 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 = 63.10 --- (1)
5 marbles + 4 beads = 63.10 - 6.50 = 56.60 --- (2)
(1) + (2)
9 marbles + 9 beads = 119.70 --- (3)
(3)
÷ 9 1 marble + 1 bead = 119.70 ÷ 9 = 13.30 --- (4)
Cost of 1 marble and 1 bead = $13.30
(b)
(4)
x 4 4 marbles + 4 beads = 4 x 13.30 = 53.20 --- (5)
(2) - (5)
5 marbles + 4 beads - 4 marbles - 4 beads = 56.60 - 53.20
5 marbles - 4 marbles - 4 beads + 4 beads = 3.40
1 marble = 3.40
Cost of 1 marble = $3.40
(c)
Substitute 1 marble = 3.40 into (4).
1 marble + 1 bead = 13.30
3.40 + 1 bead = 13.30
1 bead = 13.30 - 3.40 = 9.90
Cost of 1 bead = $9.90
Answer(s): (a) $13.30; (b) $3.40; (c) $9.90