Speed of a boat in standing water is 9 kmph and the speed of the stream is 1.5 kmph. A man rows to a place at a distance of 105 km and comes back to the starting point. The total time taken by him is:
16 hours
18 hours
20 hours
24 hours
Explanation:
Speed upstream = 7.5 kmph.
Speed downstream = 10.5 kmph.
| $\therefore$ Total time taken =$ \left(\dfrac{105}{7.5} +\dfrac{105}{10.5} \right) $hours = 24 hours. |