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/h
You need to login to perform this action.
You will be redirected in
3 sec
