Adam spends $13.50 on 3 beads and 4 marbles.
A bead costs $1.70 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 + 1.70
Total cost of 3 beads and 4 marbles
= 3(1 u + 1.70) + 4 u
= 3 u + 5.10 + 4 u
= 3 u + 4 u + 5.10
= 7 u + 5.10
7 u + 5.10 = 13.50
7 u = 13.50 - 5.10
7 u = 8.40
1 u = 8.40 ÷ 7 = 1.20
Cost of 1 bead
= 1 u + 1.70
= 1.20 + 1.70
= $2.90
(b)
Cost of 7 beads
= 7 x 2.90
= $20.30
(c)
Cost of 1 marble and 7 beads
= 1.20 + 20.30
= $21.50
(d)
Cost of 7 beads more than 1 marble
= 20.30 - 1.20
= $19.10
Answer(s): (a) $2.90; (b) $20.30; (c) $21.50; (d) $19.10