Adam spends $16.20 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 = 16.20
1 u = 16.20 ÷ 9 = 1.80
Cost of 1 marble
= 3 u
= 3 x 1.80
= $5.40
(b)
Cost of 4 marbles
= 4 x 5.40
= $21.60
(c)
Cost of 1 bead and 4 marbles
= 1.80 + 21.60
= $23.40
(d)
Cost of 1 bead less than 4 marbles
= 21.60 - 1.80
= $19.80
Answer(s): (a) $5.40; (b) $21.60; (c) $23.40; (d) $19.80