Adam spends $13.30 on 2 marbles and 3 beads.
A marble costs $2.90 more than 1 bead.
- How much does 1 marble cost?
- How much do 3 marbles cost?
- How much do a bead and 3 marbles cost?
- How much do 3 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 + 2.90
Total cost of 2 marbles and 3 beads
= 2(1 u + 2.90) + 3 u
= 2 u + 5.80 + 3 u
= 2 u + 3 u + 5.80
= 5 u + 5.80
5 u + 5.80 = 13.30
5 u = 13.30 - 5.80
5 u = 7.50
1 u = 7.50 ÷ 5 = 1.50
Cost of 1 marble
= 1 u + 2.90
= 1.50 + 2.90
= $4.40
(b)
Cost of 3 marbles
= 3 x 4.40
= $13.20
(c)
Cost of 1 bead and 3 marbles
= 1.50 + 13.20
= $14.70
(d)
Cost of 3 marbles more than 1 bead
= 13.20 - 1.50
= $11.70
Answer(s): (a) $4.40; (b) $13.20; (c) $14.70; (d) $11.70