Subject: mathqa
Question: speed of a boat in standing water is 10 kmph and speed of the stream is 2.5 kmph . a man can rows to a place at a distance of 105 km and comes back to the starting point . the total time taken by him is ?
Option: 
A: 23.4 hours
B: 21.4 hours
C: 22.4 hours
D: 19.4 hours
Answer: C