A) 2 km/h
B) 1 km/h
C) 3 km/h
D) 6 km/h
E) 3/2 km/h
Correct Answer: C
Solution :
In\[\Delta ADC,\] \[\tan \theta =\frac{6}{x+y}\] and in\[\Delta BCE,\] \[\therefore \] \[\frac{2}{x}=\frac{6}{x+y}\Rightarrow x+y=3x\] \[\Rightarrow \] \[y=2x\] On differentiating w.r.t. t, we get \[\frac{dy}{dt}=2\frac{dx}{dt}\] \[\Rightarrow \] \[6=2\frac{dx}{dt}\] \[\left( \because \frac{dy}{dt}=6given \right)\] \[\Rightarrow \] \[\frac{dx}{dt}=3\,km/h\]You need to login to perform this action.
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