A swimmer swims from a point A against a current for 10 minutes before he reaches point C and then s...........

Quant (SSC) Boats and Streams

A swimmer swims from a point A against a current for 10 minutes before he reaches point C and then swims back along the current for next 10 minutes and comes to point B. If the distance between A and B is 200 metres, find the speed of the current (in kmph) :

0.6

0.5

0.4

0.9

छोटे Courses बड़े Results

Master Boats and Streams

Prepare through Micro-courses

Try Now

Explanation:

The distance covered against the current = AC = d metres
Given AB = 200 metres
∴  BC = ( 200 + d) metres
B---------200--------A----------d-----------C
Let the speed of the man be u metres per minute and that of the current be v metres per minute
∴   Rate upstream = (u – v) m/min and Rate downstream = (u + v) m/min
Now, d /u - v = 10 ........(i)
⇒ d = 10 (u – v)
Again, 200 + d / u + v = 10 ........(ii)
Putting the value of d in eq (ii)
200 + 10(u – v) = 10u + 10v
⇒ 200u + 10u – 10v = 10u + 10v
⇒ 20v = 200
⇒ v = 10 m/min
∴   speed of the current = 10 /1000 x 60 kmph
= Putting the value of d in eq (ii)
200 + 10(u – v) = 10u + 10v
⇒ 200u + 10u – 10v = 10u + 10v
⇒ 20v = 200
⇒ v = 10 m/min
∴ speed of the current = 10/1000 x 60 kmph = 0.6 kmph