(A) 0.56 Km/h
(B) 0.60 Km/h
(C) 0.75 Km/h
(D) 0.90 Km/h
Correct Option is: C
Given that the speed in still water = 2.5 km/hr
Let the speed of the stream be ‘x; km/hr
speed in upstream = (2.5 – x)km/hr
Then time taken to cover 6.5 km downstream = 6.5 / (2.5+x)
Then time taken to cover 3.5 km upstream = 3.5 / (2.5 – x)
6.5 / (2.5 + x) = 3.5 / (2.5 – x)
6.5 (2.5 – x) = 3.5 (2.5 + x)
16.25 – 6.5x = 8.75 + 3.5x
10 x = 7.5
x = 0.75 km/hr
The speed of the stream is 0.75 km/hr