Adam spends $12.30 on 2 marbles and 3 beads.
A marble costs $2.40 more than 1 bead.
- How much does 1 marble cost?
- How much do 6 marbles cost?
- How much do a bead and 6 marbles cost?
- How much do 6 marbles cost more than 1 bead?
(a)
Let the cheaper item be 1 u.
Cost of 1 bead = 1 u
Cost of 1 marble = 1 u + 2.40
Total cost of 2 marbles and 3 beads
= 2(1 u + 2.40) + 3 u
= 2 u + 4.80 + 3 u
= 2 u + 3 u + 4.80
= 5 u + 4.80
5 u + 4.80 = 12.30
5 u = 12.30 - 4.80
5 u = 7.50
1 u = 7.50 ÷ 5 = 1.50
Cost of 1 marble
= 1 u + 2.40
= 1.50 + 2.40
= $3.90
(b)
Cost of 6 marbles
= 6 x 3.90
= $23.40
(c)
Cost of 1 bead and 6 marbles
= 1.50 + 23.40
= $24.90
(d)
Cost of 6 marbles more than 1 bead
= 23.40 - 1.50
= $21.90
Answer(s): (a) $3.90; (b) $23.40; (c) $24.90; (d) $21.90