Adam spends $16.10 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 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 = 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 = 16.10
1 u = 16.10 ÷ 7 = 2.30
Cost of 1 marble
= 2 u
= 2 x 2.30
= $4.60
(b)
Cost of 3 marbles
= 3 x 4.60
= $13.80
(c)
Cost of 1 bead and 3 marbles
= 2.30 + 13.80
= $16.10
(d)
Cost of 1 bead less than 3 marbles
= 13.80 - 2.30
= $11.50
Answer(s): (a) $4.60; (b) $13.80; (c) $16.10; (d) $11.50