A man walks to a viewpoint and returns to the starting point by his car maintaining constant speed and thus takes a total time of 9 hours 30 minutes. He would have gained 7 hours by driving both ways. How long would it have taken for him to walk both ways with same walking speed?
1
16 hours 45 minutes
2
15 hours 15 minutes
3
16 hours 30 minutes
4
17 hours 30 minutes