Imports System

Public Module Module1

    Public Sub Main()   

        Dim rate = 0.0499 / 12

        Dim result = Payment(rate, 60, 10000)

        Console.WriteLine(result)

    End Sub

     Public Function Payment(ByVal interest_rate As Double, _

                                       ByVal periods As Double, _

                                       ByVal starting_amount As Double) As Double

            If periods <= 0 Then

                Return starting_amount

            End If

            If periods <= 1.0 Then

                Return starting_amount * (interest_rate + 1.0)

            End If

            If interest_rate = 0 Then

                Return starting_amount / periods

            End If

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            Return (starting_amount * interest_rate) / (1.0 - (Math.Pow(1.0 + interest_rate, -1.0 * periods)))

        End Function

End Module

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