Adam spends $16.90 on 2 marbles and 3 beads.
A marble costs 5 times as much as 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 does 1 bead cost less than 3 marbles?
(a)
Let the cheaper item be 1 u.
Cost of 1 bead = 1 u
Cost of 1 marble = 5 u
Cost of 2 marbles = 2 x 5 u = 10 u
Cost of 3 beads = 3 x 1 u = 3 u
Total cost of 2 marbles and 3 beads
= 10 u + 3 u
= 13 u
13 u = 16.90
1 u = 16.90 ÷ 13 = 1.30
Cost of 1 marble
= 5 u
= 5 x 1.30
= $6.50
(b)
Cost of 3 marbles
= 3 x 6.50
= $19.50
(c)
Cost of 1 bead and 3 marbles
= 1.30 + 19.50
= $20.80
(d)
Cost of 1 bead less than 3 marbles
= 19.50 - 1.30
= $18.20
Answer(s): (a) $6.50; (b) $19.50; (c) $20.80; (d) $18.20