A man rows 12 km in 5 hours against the stream and the speed of current being 4 kmph. What time will be taken by him to row 15 km with the stream?
A. 1 hour $${\text{27}}\frac{7}{{13}}$$ minutes
B. 1 hour $${\text{24}}\frac{7}{{13}}$$ minutes
C. 1 hour $${\text{25}}\frac{7}{{13}}$$ minutes
D. 1 hour $${\text{26}}\frac{7}{{13}}$$ minutes
Answer: Option D
Solution(By Examveda Team)
$$\eqalign{ & {\text{According to question,}} \cr & {\text{Speed of current }}y = {\text{ }}4{\text{ }}km/h \cr & {\text{Distance = }}12{\text{ }}km \cr & {\text{Speed in upstream }} \cr & {\text{ = }}\left( {x - y} \right)km/hr. \cr & {\text{Here }}x{\text{ is speed of boat in still water}} \cr & \,{\text{ = }}\frac{{{\text{Distance}}}}{{{\text{Time}}}} \cr & x - 4 = \frac{{12}}{5} \cr & 5x - 20 = 12 \cr & 5x = 32 \cr & x = 6.4\,km/hr \cr & {\text{Speed in downstream }} \cr & {\text{ = }}\left( {x + y} \right) = 6.4 + 4 \cr & = 10.4\,km/h \cr & \therefore {\text{Time = }}\frac{{{\text{Distance}}}}{{{\text{Speed }}}} \cr & {\text{Time = }}\frac{{15}}{{10.4}} = \frac{{150}}{{104}} \cr & = 1\,{\text{hour}}\,\,26\frac{7}{{13}}\,\,{\text{minutes}} \cr} $$Related Questions on Boats and Streams
A. 2 hours
B. 3 hours
C. 4 hours
D. 5 hours
E. None of these
A. 8.5 km/hr
B. 9 km/hr
C. 10 km/hr
D. 12.5 km/hr
E. None of these
A. 2 : 1
B. 3 : 2
C. 8 : 3
D. Cannot be determined
E. None of these
A. 4 km/hr
B. 5 km/hr
C. 6 km/hr
D. 10 km/hr
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