I've got a table that gives me a datetime expression for "case creation" and "case close". I would like to find how many Business Hours a case remained open for as contact resolution is one of our KPI's.

Case Creation Example 2017-09-25 14:15:07.000000

Case Closed Example 2017-09-25 16:06:02.000000

Business Hours

Monday to Friday 09:00 AM to 18:00 PM

Is there a formula that would allow to do this?

Thanks