<PRE><B>Question 272667</B>
A boat travels at the rate of 8kph in still water, If it can travel a given distance upstream in 5 hours and the same distance in 3 hours, what is the rate of the current?

Let the speed of the current be x

upstream the boat will lose speed by x mph.

So the boats speed will be 8-x mph

Time taken is 5 hours
So distance traveled is rate * time

(8-x)  * 5

Downstream the boat will gain speed .

So the speed will be 8+x

Distance traveled = 3*(8+x)

Since the distance upstream and donstream are same

5*(8-x)= 3*(8+x)

40-5x= 24+3x

40-24= 3x+5x

16=8x

16/8=x

x=2

Speed of the current = 2mph 



</PRE>