В заданном файле целых чисел найти среднее арифметическое всех чисел, находящихся на позициях, кратных 3 - VB

Private Sub cmdCalc_Click()
    Dim fNum As Integer, N As Long, ct As Long, a As Long, i As Integer
    fNum = FreeFile
    Open App.Path & "\Data.bin" For Random As fNum Len = 2 '<<<<<
    For N = 3 To LOF(fNum) / 2 Step 3 '<<<<<
        Get fNum, N, i
        a = a + i
    Next
    ct = LOF(fNum) / 2 \ 3 '<<<<<
    Close fNum
    MsgBox "Среднее арифметическое = " & a / ct
End Sub
 
Private Sub cmdCreateFile_Click()
    Dim N As Long, z As Long, fNum As Integer, ct As Long, a As Long, i As Integer
    fNum = FreeFile
    Randomize
    If Not Dir(App.Path & "\Data.bin") = vbNullString Then Kill (App.Path & "\Data.bin")
    Open App.Path & "\Data.bin" For Binary As fNum
    N = Int(Rnd * 51) + 50  'Размер файла случаен 50..100 слов
    For z = 1 To N
        i = CInt(Int(Rnd * 65535) - 32767)
        Put fNum, , i
        If z Mod 3 = 0 Then a = a + i: ct = ct + 1
    Next
    Close fNum
    MsgBox "Среднее арифметическое = " & a / ct
End Sub