Adam spends $16.20 on 3 beads and 4 marbles.
A bead costs $1.90 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 + 1.90
Total cost of 3 beads and 4 marbles
= 3(1 u + 1.90) + 4 u
= 3 u + 5.70 + 4 u
= 3 u + 4 u + 5.70
= 7 u + 5.70
7 u + 5.70 = 16.20
7 u = 16.20 - 5.70
7 u = 10.50
1 u = 10.50 ÷ 7 = 1.50
Cost of 1 bead
= 1 u + 1.90
= 1.50 + 1.90
= $3.40
(b)
Cost of 4 beads
= 4 x 3.40
= $13.60
(c)
Cost of 1 marble and 4 beads
= 1.50 + 13.60
= $15.10
(d)
Cost of 4 beads more than 1 marble
= 13.60 - 1.50
= $12.10
Answer(s): (a) $3.40; (b) $13.60; (c) $15.10; (d) $12.10