Adam spends $15.30 on 5 beads and 6 marbles.
A bead costs $1.30 more than 1 marble.
- How much does 1 bead cost?
- How much do 7 beads cost?
- How much do a marble and 7 beads cost?
- How much do 7 beads cost more than 1 marble?
(a)
Let the cheaper item be 1 u.
Cost of 1 marble = 1 u
Cost of 1 bead = 1 u + 1.30
Total cost of 5 beads and 6 marbles
= 5(1 u + 1.30) + 6 u
= 5 u + 6.50 + 6 u
= 5 u + 6 u + 6.50
= 11 u + 6.50
11 u + 6.50 = 15.30
11 u = 15.30 - 6.50
11 u = 8.80
1 u = 8.80 ÷ 11 = 0.80
Cost of 1 bead
= 1 u + 1.30
= 0.80 + 1.30
= $2.10
(b)
Cost of 7 beads
= 7 x 2.10
= $14.70
(c)
Cost of 1 marble and 7 beads
= 0.80 + 14.70
= $15.50
(d)
Cost of 7 beads more than 1 marble
= 14.70 - 0.80
= $13.90
Answer(s): (a) $2.10; (b) $14.70; (c) $15.50; (d) $13.90