Arun
Last Activity: 7 Years ago
Dear Student
(a)
if he is swimming with the stream, the resultant velocity = 6+2 = 8 km/hr
= 8 * 5/18 = 20/9 m/sec
now
time = distance /speed = 400/ (20/9)
= 180 sec = 3 minutes
(b)
if against the stream, resultant velocity = 6 – 2 = 4 km/hr
= 4 * 5/18 = 10/9 m/sec
hence time taken = 400 / (10/9)
= 360 sec = 6 minutes
Regards
Arun (askIITians forum expert)