Adam spends $16.90 on 4 marbles and 5 beads.
A marble costs $2.20 more than 1 bead.
- How much does 1 marble cost?
- How much do 8 marbles cost?
- How much do a bead and 8 marbles cost?
- How much do 8 marbles cost more than 1 bead?
(a)
Let the cheaper item be 1 u.
Cost of 1 bead = 1 u
Cost of 1 marble = 1 u + 2.20
Total cost of 4 marbles and 5 beads
= 4(1 u + 2.20) + 5 u
= 4 u + 8.80 + 5 u
= 4 u + 5 u + 8.80
= 9 u + 8.80
9 u + 8.80 = 16.90
9 u = 16.90 - 8.80
9 u = 8.10
1 u = 8.10 ÷ 9 = 0.90
Cost of 1 marble
= 1 u + 2.20
= 0.90 + 2.20
= $3.10
(b)
Cost of 8 marbles
= 8 x 3.10
= $24.80
(c)
Cost of 1 bead and 8 marbles
= 0.90 + 24.80
= $25.70
(d)
Cost of 8 marbles more than 1 bead
= 24.80 - 0.90
= $23.90
Answer(s): (a) $3.10; (b) $24.80; (c) $25.70; (d) $23.90
