title: Calculate difference between 2 times in hours in PHP
body: <p>I have two times - 
  For eg- the current time  - 08:24 and date is 02/01/2013 in dd/mm/yyyy format
  and I have another time at 13:46 and date is 31/12/2012 . So, how can I calculate the difference between the 2 times in hours using PHP. (i.e. 42.63 hours)
  Thanks in advance.</p>