A man can row 7 ½ kms on hour in still water and he finds that it takes hi twice as long to row down the river. The rate of stream is
Answer: B
Let the rate of the stream be x km/hr.
Then Speed downstream = (15/2 + x)km/hr.
Speed upstream = (15/2 -x)km/hr
(15/2 + x) = 2 (15/2 - x)
=> 3x =15/2
=> x = 15/6 = 5/2 = 2.5
Therefore, Rate of stream = 2.5 km/hr