Speed of a boat in standing water is 9 kmph and the speed of the stream is 6 kmph. A man rows to place at a distance of 170 km and comes back to the starting point. The total time taken by him is:	Answers: A) 12 hours B) 68 hours C) 36 hours D) 58 hours E) None
Sol.   Speed upstream = 3 kmph; Speed downstream = 15 kmph.   ∴ total time taken = [105/7.5 + 105/10.5] hours = 68 hours.   Answer 68 hours
<result>B</result>
Speed of a boat in standing water is 9 kmph and the speed of the stream is 6 kmph. A man rows to place at a distance of 170 km and comes back to the starting point. The total time taken by him is: