Adam spends $16.70 on 2 marbles and 3 beads.
A marble costs $2.10 more than 1 bead.
- How much does 1 marble cost?
- How much do 3 marbles cost?
- How much do a bead and 3 marbles cost?
- How much do 3 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 + 2.10
Total cost of 2 marbles and 3 beads
= 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 = 16.70
5 u = 16.70 - 4.20
5 u = 12.50
1 u = 12.50 ÷ 5 = 2.50
Cost of 1 marble
= 1 u + 2.10
= 2.50 + 2.10
= $4.60
(b)
Cost of 3 marbles
= 3 x 4.60
= $13.80
(c)
Cost of 1 bead and 3 marbles
= 2.50 + 13.80
= $16.30
(d)
Cost of 3 marbles more than 1 bead
= 13.80 - 2.50
= $11.30
Answer(s): (a) $4.60; (b) $13.80; (c) $16.30; (d) $11.30