UPSC CAPF AC 2020 Paper

Let when the length of wires is 6m, then radius = x m
∴ New radius = x ×

80

100

=

4

3

xm
Now, let the length of wires = h m
According to the question, volumes are same.
∴ π × x2 × 6 = π × (

4

5

x)2 × h
⇒ π × x2 × 6 = π ×

16

25

x2 × h
⇒ h =

6×25

16

=

75

8

Hence, required percentage increases
=

( 75 8 −6)

6

× 100
=

27

(8×6)

× 100
= 56.25 %