Question

The radius of a wire is decreased to one-third. If volume remains the same, the length will become

(a) 3 times

(b) 6 times

(c) 9 times

(d) 27 times

Answer 1

Let V₁ and V₂ be the volume of the two cylinders with h₁ and h₂ as their heights:

Let r₁ and r₂ be their base radius.

It is given that

Hence, the length will become 9 times.

Hence, the correct option is (c)