Water flows into a tank 200 m x 160 m througb a rectangular pipe of 1.5m x 1.25 m @  20 kmph . In what time (in minutes) will the water rise by metres?

Volume required in the tank = (200 x 150 x 2) m³ = 60000 m³
Length of water column flown in1 min =(20*1000)/60 m =1000/
 Volume flown per minute = 1.5 * 1.25 * (1000/3) m³ = 625 m³.

 Required time = (60000/625)min = 96min