A) 22 km/hr.
B) 19 km/hr.
C) 21 km/hr.
D) 25 km/hr.
Correct Answer: A
Solution :
[a] Let speed in still water = x km/h Speed of stream = 2 km/h \[\therefore \,\,\,\frac{10}{x+2}+\frac{10}{x-2}=\frac{55}{60}\] \[10x+10x=\frac{11}{12}\left( {{x}^{2}}-4 \right)\] \[11{{x}^{2}}-240x-44=0\] x = 22 \[\therefore \] speed in still water = 22 km/hYou need to login to perform this action.
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