Sub AddMinutes(TimeString As String, add As Int) As String
Dim i As Int = TimeString.IndexOf(":")
Dim hours As Int = TimeString.SubString2(0, i)
Dim minutes As Int = TimeString.SubString(i + 1)
minutes = minutes + add
hours = hours + minutes / 60
minutes = minutes Mod 60
Return NumberFormat(hours, 2, 0) & ":" & NumberFormat(minutes, 2, 0)
End Sub