Adam spends $14.50 on 3 marbles and 4 beads.
A marble costs $1.10 more than 1 bead.
- How much does 1 marble cost?
- How much do 4 marbles cost?
- How much do a bead and 4 marbles cost?
- How much do 4 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 + 1.10
Total cost of 3 marbles and 4 beads
= 3(1 u + 1.10) + 4 u
= 3 u + 3.30 + 4 u
= 3 u + 4 u + 3.30
= 7 u + 3.30
7 u + 3.30 = 14.50
7 u = 14.50 - 3.30
7 u = 11.20
1 u = 11.20 ÷ 7 = 1.60
Cost of 1 marble
= 1 u + 1.10
= 1.60 + 1.10
= $2.70
(b)
Cost of 4 marbles
= 4 x 2.70
= $10.80
(c)
Cost of 1 bead and 4 marbles
= 1.60 + 10.80
= $12.40
(d)
Cost of 4 marbles more than 1 bead
= 10.80 - 1.60
= $9.20
Answer(s): (a) $2.70; (b) $10.80; (c) $12.40; (d) $9.20