1.  A man takes 5 hours 45 min. in walking to a certain place and riding back. He would have gained 2 hours by riding both ways. The time he would take to walk both ways, is :

A. 3 hrs 45 min
B. 7 hrs 30 min
C. 7 hrs 45 min
D. 11 hrs 45 min

Answer: Option C

Explanation:

Let the distance be x km.
Then,
(Time taken to walk x km) + (Time taken to ride x km) = 23/4 hrs.
=> (Time taken to walk 2x km) + (Time taken to ride 2x km) = 23/2 hrs.

But, time taken to ride 2x km = 15/4 hrs.
∴ Time taken to walk 2x km = ( 23/2 - 15/4) hrs
= 31/4 hrs
= 7 hrs 45 min.