Adam spends $14.90 on 2 marbles and 3 beads.
A marble costs $2.70 more than 1 bead.
- How much does 1 marble cost?
- How much do 7 marbles cost?
- How much do a bead and 7 marbles cost?
- How much do 7 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 + 2.70
Total cost of 2 marbles and 3 beads
= 2(1 u + 2.70) + 3 u
= 2 u + 5.40 + 3 u
= 2 u + 3 u + 5.40
= 5 u + 5.40
5 u + 5.40 = 14.90
5 u = 14.90 - 5.40
5 u = 9.50
1 u = 9.50 ÷ 5 = 1.90
Cost of 1 marble
= 1 u + 2.70
= 1.90 + 2.70
= $4.60
(b)
Cost of 7 marbles
= 7 x 4.60
= $32.20
(c)
Cost of 1 bead and 7 marbles
= 1.90 + 32.20
= $34.10
(d)
Cost of 7 marbles more than 1 bead
= 32.20 - 1.90
= $30.30
Answer(s): (a) $4.60; (b) $32.20; (c) $34.10; (d) $30.30