A rectangular tank is 80 m long and 25 m broad. Water flows into it through a pipe whose cross-section is 25 cm2, at the rate of 16 km per hour. How much the level of the water rises in the tank in 45 minutes.
Solution
Let the level of water be risen by h cm.
Then,
Volume of water in the tank = `8000xx2500xxhcm^2`
Area of cross – section of the pipe =`25cm^2`
Water coming out of the pipe forms a cuboid of base area `25cm^2` and length equal to the distance travelled in 45 minutes with the speed 16km/hour.
i.e., length=`16000xx100xx45/60cm`
∴Volume of water coming out of pipe in 45 minutes
`=25xx16000xx100(45/60)`
Now, volume of water in the tank = volume of water coming out of the pipe in 45 minutes
`⇒8000xx2500xxh=16000xx100xx45/60xx25`
`⇒h=(16000xx100xx45xx25)/(8000xx2500xx60)cm=1.5cm.`
