Adam spends $12.10 on 2 marbles and 3 beads.
A marble costs $1.30 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 + 1.30
Total cost of 2 marbles and 3 beads
= 2(1 u + 1.30) + 3 u
= 2 u + 2.60 + 3 u
= 2 u + 3 u + 2.60
= 5 u + 2.60
5 u + 2.60 = 12.10
5 u = 12.10 - 2.60
5 u = 9.50
1 u = 9.50 ÷ 5 = 1.90
Cost of 1 marble
= 1 u + 1.30
= 1.90 + 1.30
= $3.20
(b)
Cost of 3 marbles
= 3 x 3.20
= $9.60
(c)
Cost of 1 bead and 3 marbles
= 1.90 + 9.60
= $11.50
(d)
Cost of 3 marbles more than 1 bead
= 9.60 - 1.90
= $7.70
Answer(s): (a) $3.20; (b) $9.60; (c) $11.50; (d) $7.70