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 :
Choose the correct choice from the following answers:
A) 11 hrs 45 min  B) 3 hrs 45 min  C) 7 hrs 30 min  D) 7 hrs 45 min  E) None
Sol.   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) + (Tie 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.   11 hrs 45 minnswer 11 hrs 45 min
<result>A</result>
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 :