Question

Water is being pumped out through a circular pipe whose internal diameter is 7 cm. If the flow of water is 72 cm per second, how many litres of water are being pumped out in one hour?

• A. 2772 litres
• B. 9979 litres
• C. 9979.2 litres
• D. 9297.4 litres

Answer 1

Answer: (C)

9979.2 litres

According to question

Diameter of pipe $=7cm$

Thus,

Radius of pipe $=r=\frac{7}{2}cm$

Let length of pipe be $L$.

Rate of flow of water through pipe $=72cmpersec$

Thus,

In $1sec$ water flowed $=72cm$

Thus,

In $60sec=72\times 60$

In $1hr=72\times 60\times 60$

So clearly,

Volume of water flowed $=\pi r^{2}H$

$=\frac{22}{7}\times \frac{49}{4}\times 72\times 60\times 60$

$=9979200c{m}^3$

$=9979.2Liter$

Hence, this is the answer.