GMAT Resources

Man rows 135 km upstream in 2.7 hours. Find the Speed of the man.

Man rows 135 km upstream in 2.7 hours. Find the Speed of the man.

Downstream: In water, the direction along the stream is called downstream.

If the speed of a boat in still water is u km/hr and the speed of the stream is v km/hr, then

Speed downstream = (u + v) km/hr

Upstream: In water, the direction against the stream is called upstream.

Speed upstream = (u – v) km/hr
——————————————————————————————————————————

Now, suppose if the speed downstream is already given as x km/hr and the speed upstream is given as y km/hr, then

Speed in still water = (x + y) / 2 km/hr

Speed of the stream = (x − y) / 2 km/hr

——————————————————————————————————————————-

Suppose a man swims at the speed of x km/hr in still water and he swims the same distance up and down in a stream which flows at a rate of y km/hr.

Then his average speed throughout the journey = (Speed downstream × Speed upstream) / (Speed in still water) = (x+y) * (x−y) / x

Solve the following question –

A man rows 135 km upstream in 2.7 hours. He rows the same distance downstream in 2.5 hours. However for downstream, he reduces his speed by 9%, while speed of the current gets reduced by 20%.

Find the Speed of the man.

Submit your solution here.

img credit: BBC



Sign up for our newsletter!

Get expert tips, exam updates and news articles to help improve your test score

SIGN UP

Live Classes

Take online classes to learn from the subject experts

REGISTER