Adam spends $13.80 on 5 beads and 6 marbles.
A bead costs $2.10 more than 1 marble.
- How much does 1 bead cost?
- How much do 8 beads cost?
- How much do a marble and 8 beads cost?
- How much do 8 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 + 2.10
Total cost of 5 beads and 6 marbles
= 5(1 u + 2.10) + 6 u
= 5 u + 10.50 + 6 u
= 5 u + 6 u + 10.50
= 11 u + 10.50
11 u + 10.50 = 13.80
11 u = 13.80 - 10.50
11 u = 3.30
1 u = 3.30 ÷ 11 = 0.30
Cost of 1 bead
= 1 u + 2.10
= 0.30 + 2.10
= $2.40
(b)
Cost of 8 beads
= 8 x 2.40
= $19.20
(c)
Cost of 1 marble and 8 beads
= 0.30 + 19.20
= $19.50
(d)
Cost of 8 beads more than 1 marble
= 19.20 - 0.30
= $18.90
Answer(s): (a) $2.40; (b) $19.20; (c) $19.50; (d) $18.90