Adam spends $16.80 on 2 beads and 3 marbles.
A bead costs 2 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 = 2 u
Cost of 2 beads = 2 x 2 u = 4 u
Cost of 3 marbles = 3 x 1 u = 3 u
Total cost of 2 beads and 3 marbles
= 4 u + 3 u
= 7 u
7 u = 16.80
1 u = 16.80 ÷ 7 = 2.40
Cost of 1 bead
= 2 u
= 2 x 2.40
= $4.80
(b)
Cost of 4 beads
= 4 x 4.80
= $19.20
(c)
Cost of 1 marble and 4 beads
= 2.40 + 19.20
= $21.60
(d)
Cost of 1 marble less than 4 beads
= 19.20 - 2.40
= $16.80
Answer(s): (a) $4.80; (b) $19.20; (c) $21.60; (d) $16.80