Adam spends $12.70 on 2 beads and 3 marbles.
A bead costs $2.10 more than 1 marble.
- How much does 1 bead cost?
- How much do 4 beads cost?
- How much do a marble and 4 beads cost?
- How much do 4 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 2 beads and 3 marbles
= 2(1 u + 2.10) + 3 u
= 2 u + 4.20 + 3 u
= 2 u + 3 u + 4.20
= 5 u + 4.20
5 u + 4.20 = 12.70
5 u = 12.70 - 4.20
5 u = 8.50
1 u = 8.50 ÷ 5 = 1.70
Cost of 1 bead
= 1 u + 2.10
= 1.70 + 2.10
= $3.80
(b)
Cost of 4 beads
= 4 x 3.80
= $15.20
(c)
Cost of 1 marble and 4 beads
= 1.70 + 15.20
= $16.90
(d)
Cost of 4 beads more than 1 marble
= 15.20 - 1.70
= $13.50
Answer(s): (a) $3.80; (b) $15.20; (c) $16.90; (d) $13.50