A) 1 km/hr
B) 2 km/hr
C) 3 km/hr
D) 4 km/hr
Correct Answer: C
Solution :
Here: speed of boat in still water \[{{\upsilon }_{b}}\,=5\,\,km/hr\] width of river = 1 km Time taken to cross the river along shortest possible path = 15 min = \[\frac{1}{4}\] hour Hence resultant velocity of the boat \[=4\,km\text{/}hr\] Then the velocity of river \[=\sqrt{{{(5)}^{2}}-{{(4)}^{2}}}=3\,km\text{/}hr\]You need to login to perform this action.
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