Water flows through a cylindrical pipe of an internal diameter of 7cm at the rate of 5m/s. The time, in minutes, the pipe would take to fill an empty rectangular tank of 4m × 3m × 2.31m is -

Question: Water flows through a cylindrical pipe of an internal diameter of 7cm at the rate of 5m/s. The time, in minutes, the pipe would take to fill an empty rectangular tank of 4m × 3m × 2.31m is -

Solution:
the total volume of the tank is = 400 × 300 × 231 cc
total water flow per second through the pipe is = πr²h
= (22/7) × (7/2)² × 500

∴ total time = (400 × 300 × 231)/{(22/7) × (7/2)² × 500}
= (400 × 300 × 231 × 4 × 7)/(22 × 49 × 500)
= 1440 s
= 24 min