Adam spends $12.10 on 5 marbles and 6 beads.
A marble costs $1.10 more than 1 bead.
- How much does 1 marble cost?
- How much do 7 marbles cost?
- How much do a bead and 7 marbles cost?
- How much do 7 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 5 marbles and 6 beads
= 5(1 u + 1.10) + 6 u
= 5 u + 5.50 + 6 u
= 5 u + 6 u + 5.50
= 11 u + 5.50
11 u + 5.50 = 12.10
11 u = 12.10 - 5.50
11 u = 6.60
1 u = 6.60 ÷ 11 = 0.60
Cost of 1 marble
= 1 u + 1.10
= 0.60 + 1.10
= $1.70
(b)
Cost of 7 marbles
= 7 x 1.70
= $11.90
(c)
Cost of 1 bead and 7 marbles
= 0.60 + 11.90
= $12.50
(d)
Cost of 7 marbles more than 1 bead
= 11.90 - 0.60
= $11.30
Answer(s): (a) $1.70; (b) $11.90; (c) $12.50; (d) $11.30