Let u and v represent the velocity of the river and that of the man, respectively
From the following figure, we see that for the man to travel by the shortest route AC
()， velocity of the man must lie along AB .
Using the law of vector addition,
+ =
Given:
u = 2 km/h
v = 5 km/h
The direction (6) in which the man should swim is given by
sin θ =
=
⇒ sin θ =
= 0.4
⇒ θ =
sin−1(0.4) Thus, the man should swim at an angle of "
sin−1(0.4) West of North".
Hence, option 'C' is correct.