how to Calculate the Target Date ad time based given date and time

hi team,

am looking for some help in calculating the Target time ,
cell A2: date and time (Manual)
B2= Formula to get the target date and time.
Condition: exclude (Saturday & Sunday), public holidays,and off working hours(i.e: Business hours of the working day is 08:00 AM to 06:00 PM)

30:00 and 50:00 is the target what ever the target i put in cell reference it should give the target time accordingly

Exp:

Start: 6/20/2016 8:00
Target(50): 6/27/2016 8:00 AM

Start: 6/20/2016 8:00
Target(30):6/23/2016 8:00 AM

Regards
Ravi GH

This might be helpful,


https://exceljet.net/formula/add-business-days-to-date