calculate TAT based on working hours and holidays

Hi All,

hope I can find some help here. I am trying to calculate TAT between 2 dates and based on working hours and holidays. I tried to use a formula I found here but since I am not quite an expert it returns some error that I cannot figure out.

I am attaching the test file hoping someone can give me some guidance.

Thanks so muchTAT test.xlsx

Later Edit: I apologize, yes, the working week is Monday to Friday. I would like to know how to calculate the TAT between the 2 dates keeping in mind the working week, the holidays and the working hours.