A) 2 km/h
B) 3 km/h
C) 4 km/h
D) 5 km/h
Correct Answer: D
Solution :
Distance covered upstream\[\frac{45}{4}\min =\frac{3}{4}\text{km}\] Distance covered upstream in 1 h \[=\left( \frac{3}{4}\times \frac{5}{45}\times 60 \right)\text{km/h}\] \[=4\,\,\text{km/h}\] Distance covered downstream in \[\frac{15}{2}\min =\frac{3}{4}\text{km}\] Distance covered downstream in 1 h \[=\left( \frac{3}{4}\times \frac{2}{15}\times 60 \right)\text{km/h}\] \[=6\,\,\text{km/h}\] Speed of the man in still water \[=\frac{1}{2}(6+4)\,\text{km/h}=5\,\,\text{km/h}\]You need to login to perform this action.
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