Water is flowing at the rate of 2.52 km / h through a cylindrical pipe into a cylindrical tank, the radius of the base is 40 cm. If the increase in the level of water in the tank, in half and hour is 3.15 m, find the internal diameter of the pipe.

Speed of water = 2.52kmph = 2520 m/hr


Length, h’ = 2520 m


Let the radius of the pipe be r’ and radius of the tank, r’’ = 40 cm = 0.4 m


Level of water in tank in half and hour = 3.15 m


Level of water in tank in an hour, h’’ = 6.30 m


Now, volume of pipe = volume of tank


π r’2 h’ = π r’’2 h’’


r2 (2520) = (0.4)2 (6.3)



diameter = 2r’ = 2 × 2 = 4 cm


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