Question
900 metres long train crosses a man who is moving in the
same direction with a certain speed, in 30 seconds. If the same train can cross a tree in 20 seconds with the same speed, then find the speed of the man.Solution
Speed of train = 900/20 = 45 m/sec Let the speed of the man be βsβ m/sec Relative speed of the train = (45 β s) m/sec According to the question, (45 β s) = 900/30 Or, s = 45 β 30 = 15 Therefore, speed of the man = 15 m/sec
Find the geometric mean for the series given below.
31, 93, 279
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