Code VBA:
Function NgayTra(StartDate As Date, LeTet As Range, TotalDay As Integer) As Date
i = 0
Do While i < TotalDay
If Weekday(StartDate, vbMonday) < 6 And LeTet.Find(CStr(StartDate)) Is Nothing Then i = i + 1
StartDate = StartDate + 1
Loop
NgayTra = StartDate - 1
End Function
