A boat takes 50% more time to go in upstream then the time taken by it to cover the same distance in downstream. If speed of current is 5 km/hr, then find the speed of boat in still water.

25 km/hr

50% = \(\frac{1}{2}\)

               Downstream(D.S.)   :   Upstream(U.S.)

Time    :             2                  :               3  

Speed :              3                  :               2

As we know,

Speed of boat in still water = \(\frac{D.S.\;+\;U.S.}{2}\) 

Speed of stream = \(\frac{D.S.\;-\;U.S.}{2}\)

Therefore,

               Boat           :            Stream

Speed        \(\frac{3\;+\;2}{2}\)     :         \(\frac{3\;-\;2}{2}\)

                  5            :                1

ATQ,

1R = 5 km/hr

Speed of boat in still water = 5 × 5 = 25 km/hr