Question

A cylindrical pipe has inner diameter of 4cm and water flows through it at the rate of 20m/min .how long would it take to fill a conical tank of radius 40cm and depth 72cm

Answer 1

Water is flowing at the rate of 20m/ min or 2000 cm / min

So the length of the cylindrical pipe will be 2000 cm

Now the diameter is 4cm so radius = 2cm

Volume of cylinder= pi * r * r * h
= 22/7 * 2 * 2 * 2000  cm³

Now the conical tank has radius = 40 cm and depth = 72 cm

So volume of conical tank= 1/3 * pi * r * r * h
= 1/3 * 22/7 * 40 * 40 * 72 cm ³

Time taken to fill the tank= Volume of conical tank / Volume of cylinder
= (1/3 * 22/7 * 40 * 40 * 72) / (22/7 * 2 * 2 * 2000 )
= 24/5 min
=  4.8 min  
= 4 min and 48 seconds