Adam spends $15.90 on 2 beads and 3 marbles.
A bead costs $2.20 more than 1 marble.
- How much does 1 bead cost?
- How much do 3 beads cost?
- How much do a marble and 3 beads cost?
- How much do 3 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 + 2.20
Total cost of 2 beads and 3 marbles
= 2(1 u + 2.20) + 3 u
= 2 u + 4.40 + 3 u
= 2 u + 3 u + 4.40
= 5 u + 4.40
5 u + 4.40 = 15.90
5 u = 15.90 - 4.40
5 u = 11.50
1 u = 11.50 ÷ 5 = 2.30
Cost of 1 bead
= 1 u + 2.20
= 2.30 + 2.20
= $4.50
(b)
Cost of 3 beads
= 3 x 4.50
= $13.50
(c)
Cost of 1 marble and 3 beads
= 2.30 + 13.50
= $15.80
(d)
Cost of 3 beads more than 1 marble
= 13.50 - 2.30
= $11.20
Answer(s): (a) $4.50; (b) $13.50; (c) $15.80; (d) $11.20