Speed of a boat in standing water is 10kmph and speed of the stream is 2.5kmph. A man can rows to a place at a distance of 105km and comes back to the starting point. The total time taken by him is?  Choose the correct choice from the following answers.
A) 23.4hours
B) 22.4hours
C) 21.4hours
D) 20.4hours
E) 19.4hours
Speed upstream = 7.5kmph   Speed downstream = 12.5kmph   Total time taken = 105/7.5 + 105/12.5= 
<gadget id="calculator">105/7.5 + 105/12.5</gadget>
<output>22.4</output>
22.4 hours   Answer is 22.4hours
<result>B</result>
Speed of a boat in standing water is 10kmph and speed of the stream is 2.5kmph. A man can rows to a place at a distance of 105km and comes back to the starting point. The total time taken by him is?