Adam spends $13.30 on 2 marbles and 3 beads.
A marble costs 2 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 = 2 u
Cost of 2 marbles = 2 x 2 u = 4 u
Cost of 3 beads = 3 x 1 u = 3 u
Total cost of 2 marbles and 3 beads
= 4 u + 3 u
= 7 u
7 u = 13.30
1 u = 13.30 ÷ 7 = 1.90
Cost of 1 marble
= 2 u
= 2 x 1.90
= $3.80
(b)
Cost of 4 marbles
= 4 x 3.80
= $15.20
(c)
Cost of 1 bead and 4 marbles
= 1.90 + 15.20
= $17.10
(d)
Cost of 1 bead less than 4 marbles
= 15.20 - 1.90
= $13.30
Answer(s): (a) $3.80; (b) $15.20; (c) $17.10; (d) $13.30
