Chartered Accountant
6085 Points
Joined November 2011
I think the answer is 48 hrs.
Explanation:
Lets take any one hour, say 00:00 to 01:00
In this 1 hour, the hands are straight twice - at 00:00 and 00:30.
Similiarly between 01:00 and 02:00, itsstraight at 01:05 and 01:35
This means, in any one hour, hands are straight two times.
So in 24 hrs, the hands are straight 24*2 = 48 times.