Question

A boat takes a total of 8 hours to travel 90 km upstream and the same distance downstream. The speed of the boat in still water is four times that of stream.What is the speed of the boat in still water.

Answer 1

Let ,the speed of the boat in upstream=x
Then ,the speed of the boat in still water=4x km/hr.
Now,
Distance covered by the boat in upstream =90km
Time taken=8 hrs

speed at upstream=Distance covered/Time taken
=90km/8hrs
=11.25km/hr

Then,
The speed of the boat in still war=4x
=4*11.25km/hr
=45km/hr

= Thus,we get the speed of the boat in still water is 45km/hr