Adam spends $16.20 on 2 beads and 3 marbles.
A bead costs 3 times as much as 1 marble.
- How much does 1 bead cost?
- How much do 4 beads cost?
- How much do a marble and 4 beads cost?
- How much does 1 marble cost less than 4 beads?
(a)
Let the cheaper item be 1 u.
Cost of 1 marble = 1 u
Cost of 1 bead = 3 u
Cost of 2 beads = 2 x 3 u = 6 u
Cost of 3 marbles = 3 x 1 u = 3 u
Total cost of 2 beads and 3 marbles
= 6 u + 3 u
= 9 u
9 u = 16.20
1 u = 16.20 ÷ 9 = 1.80
Cost of 1 bead
= 3 u
= 3 x 1.80
= $5.40
(b)
Cost of 4 beads
= 4 x 5.40
= $21.60
(c)
Cost of 1 marble and 4 beads
= 1.80 + 21.60
= $23.40
(d)
Cost of 1 marble less than 4 beads
= 21.60 - 1.80
= $19.80
Answer(s): (a) $5.40; (b) $21.60; (c) $23.40; (d) $19.80