A) 4.5 km/h
B) 1 km/h
C) 1.5 km/h
D) 3 km/h
Correct Answer: D
Solution :
Time taken to cross the river by shortest path = 15 min. \[\because \] \[60\,\min =1\,\text{h}\] \[\because \] \[15\,\min =\frac{1}{60}\times 15\,\text{h =}\frac{1}{4}\,\text{h}\] \[\text{Velocity =}\frac{\text{distance}}{\text{time}}=\frac{1}{1/4}=4\,km/h\] or \[{{v}_{br}}=5\,\text{km/h}\] Velocity of river is given by \[v=\sqrt{{{(5)}^{2}}-{{(4)}^{2}}}=3\,\text{km/h}\]You need to login to perform this action.
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