Adam spends $12.60 on 2 marbles and 3 beads.
A marble costs 3 times as much as 1 bead.
- How much does 1 marble cost?
- How much do 4 marbles cost?
- How much do a bead and 4 marbles cost?
- How much does 1 bead cost less than 4 marbles?
(a)
Let the cheaper item be 1 u.
Cost of 1 bead = 1 u
Cost of 1 marble = 3 u
Cost of 2 marbles = 2 x 3 u = 6 u
Cost of 3 beads = 3 x 1 u = 3 u
Total cost of 2 marbles and 3 beads
= 6 u + 3 u
= 9 u
9 u = 12.60
1 u = 12.60 ÷ 9 = 1.40
Cost of 1 marble
= 3 u
= 3 x 1.40
= $4.20
(b)
Cost of 4 marbles
= 4 x 4.20
= $16.80
(c)
Cost of 1 bead and 4 marbles
= 1.40 + 16.80
= $18.20
(d)
Cost of 1 bead less than 4 marbles
= 16.80 - 1.40
= $15.40
Answer(s): (a) $4.20; (b) $16.80; (c) $18.20; (d) $15.40