Public Function tien(tiengui As Double, ngui As Date, nrut As Date, khan As String, lsuat As Double) As Double
Dim ngay, i As Integer, arr1(), arr2()
arr1 = Array(3, 6, 9, 12, 24)
arr2 = Array(7.5, 11.2, 11.2, 11.25, 11.5)
ngay = nrut - ngui
If khan = "Không TH" Then
tien = tiengui * (1 + 0.035 / 12 * ngay)
Exit Function
End If
i = Int(ngay / Val(Left(khan, 2)) / 30)
If i <> 0 Then
tien = (tiengui * (1 + i * lsuat)) * ((ngay - i * 30) * 0.035 + 1)
Else
If ngay / 30 > 3 Then
khan = arr1(WorksheetFunction.Match(ngay / 30, arr1))
lsuat = arr2(WorksheetFunction.Match(ngay / 30, arr1))
i = Int(ngay / Val(Left(khan, 2)) / 30)
tien = (tiengui * (1 + i * lsuat)) * ((ngay - i * 30) * 0.035 + 1)
Else
tien = tiengui * (1 + 0.035 / 12 * ngay)
End If
End If
End Function