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.
Answer & explanation
Correct answer: option 4
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