Adam spends $13.80 on 5 marbles and 6 beads.
A marble costs $2.10 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 + 2.10
Total cost of 5 marbles and 6 beads
= 5(1 u + 2.10) + 6 u
= 5 u + 10.50 + 6 u
= 5 u + 6 u + 10.50
= 11 u + 10.50
11 u + 10.50 = 13.80
11 u = 13.80 - 10.50
11 u = 3.30
1 u = 3.30 ÷ 11 = 0.30
Cost of 1 marble
= 1 u + 2.10
= 0.30 + 2.10
= $2.40
(b)
Cost of 6 marbles
= 6 x 2.40
= $14.40
(c)
Cost of 1 bead and 6 marbles
= 0.30 + 14.40
= $14.70
(d)
Cost of 6 marbles more than 1 bead
= 14.40 - 0.30
= $14.10
Answer(s): (a) $2.40; (b) $14.40; (c) $14.70; (d) $14.10