How to calculate Turn Around Time (TAT) considering weekend and working Hours..!

Considering Two Set of Data Start Date "A1=22-08-2019 11:55 AM" End Date:- "B2=27-08-2019 5:00 PM"   Conditions:-  Office working Hours is 10 AM - 7 PM  Lunch is between 1 PM- 2 PM Saturday S...