Questions & Answers

Question

Answers

A.4 cm

B.10 cm

C.8 cm

D.6 cm

Answer
Verified

Given that,

Length of cylindrical water tank = 30 cm

Let its radius be r

Volume of cylindrical water tank \[ = \pi {r^2}h\]

$ = \left( {\pi {r^2} \times 30} \right)$cubic cm ….(i)

Jack fills his Hydrogenator at the rate of = π cubic cm per second

Total time taken to fill the tank = 8 min = 8 X 60 = 480 seconds

Total volume filled = (rate of filling X Time taken to fill the tank)

Thus, total volume filled $ = \left( {\pi \times 480} \right)$ cubic cm …(ii)

From equations (i) and (ii), we get;

$\pi {r^2} \times 30 = \pi \times 480$

$ \Rightarrow {r^2} = \dfrac{{480}}{{30}} = 16$cm

$ \Rightarrow r = 4$cm

Radius = 4 cm

Hence, the diameter of the circular base of the gun’s water tank is the twice of the radius $ = 2 \times 4 = 8$cm