1) Speed of boat in standing water is 9 km/h and the speed of the stream is 1.5 km/h. A man rows to place at distance of 105 km and comes back to the starting point. The total time taken by him is : A) 16 h B) 18 h C) 20 h D) 24 h E) 26 h Answer: Option DExplanation:Speed upstream = 7.5 km/h Speed downstream = 10.5 km/h Total time taken = $\frac{105}{7.5}+\frac{105}{10.5}$ = 24 hrs.
