Adam spends $15.10 on 4 marbles and 5 beads.
A marble costs $2.20 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 + 2.20
Total cost of 4 marbles and 5 beads
= 4(1 u + 2.20) + 5 u
= 4 u + 8.80 + 5 u
= 4 u + 5 u + 8.80
= 9 u + 8.80
9 u + 8.80 = 15.10
9 u = 15.10 - 8.80
9 u = 6.30
1 u = 6.30 ÷ 9 = 0.70
Cost of 1 marble
= 1 u + 2.20
= 0.70 + 2.20
= $2.90
(b)
Cost of 6 marbles
= 6 x 2.90
= $17.40
(c)
Cost of 1 bead and 6 marbles
= 0.70 + 17.40
= $18.10
(d)
Cost of 6 marbles more than 1 bead
= 17.40 - 0.70
= $16.70
Answer(s): (a) $2.90; (b) $17.40; (c) $18.10; (d) $16.70