Adam spends $16.40 on 5 beads and 6 marbles.
A bead costs $1.30 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 + 1.30
Total cost of 5 beads and 6 marbles
= 5(1 u + 1.30) + 6 u
= 5 u + 6.50 + 6 u
= 5 u + 6 u + 6.50
= 11 u + 6.50
11 u + 6.50 = 16.40
11 u = 16.40 - 6.50
11 u = 9.90
1 u = 9.90 ÷ 11 = 0.90
Cost of 1 bead
= 1 u + 1.30
= 0.90 + 1.30
= $2.20
(b)
Cost of 7 beads
= 7 x 2.20
= $15.40
(c)
Cost of 1 marble and 7 beads
= 0.90 + 15.40
= $16.30
(d)
Cost of 7 beads more than 1 marble
= 15.40 - 0.90
= $14.50
Answer(s): (a) $2.20; (b) $15.40; (c) $16.30; (d) $14.50