Water in a rectangular reservoir having base 80 m by 60 m i s 6.5 m deep. In what time can the water be emptied by a pipe ôf which the cross-section is a square of side 20 cm, if the water runs through the pipe at the rate of 15 km/hr.
Flow of water = 15km / hr
Volume of water coming out of the pipe in one hour
`"Volume of the tank"= 80xx60xx6.5`
∴Time taken to empty the tank
`="Volume of tank"/"volume of water coming out of the pipe in one hour"`