title: PHP - Calculating working hours between two dates but exclude the time when request is on hold
body: <p>Can some one help me write a function that calculates the number of working hours between two dates but want to exclude the time when the request had a status of "On Hold". </p>
  
  <p>So lets say the request came in at 3PM friday and was closed at 3PM Wednesday, and working hours are from 8AM to 5PM pacific (Mon thru Friday)...Total working hours will be 27 hours...but if the request remained on hold from Monday 3PM till Tuesday 3PM...Actual work time on the request really becomes 18 hours instead of 27 hours.</p>
  
  <p>I have recently started working on PHP and have been assigned this task which is very confusing to me. Please help</p>