The radius of a wire is decreased to one-third. If volume

Home » Aptitude » Volume and Surface Area of Solid Figures » Question

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

1. 1 time
2. 2 times
3. 6 times
4. 9 times

Correct Option: D

Let original radius = r and original length = h
New radius = r/3
Let new length = H
Then, π r²h = π (r/3)² x H = π r²H/9
∴ H = 9h
Thus, the length becomes 9 times .