'Question: Do they have the same cost?

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Imports System

Public Module Module1

    Sub Main()

        Dim a As New Book

        Dim b As New TechBook

        Dim c As New DotNetTechBook

        OutputPrice(a)

        OutputPrice(b)

        OutputPrice(c)

    End Sub

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    Private Sub OutputPrice(ByVal item As Book)

        Console.WriteLine(String$.Format("{0} costs {1}", 

item.Description, item.GetPrice))

    End Sub

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    Public Class Book

        Public Description As String

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        Public Overridable Function GetPrice() As Decimal

            Return 0.0

        End Function

    End Class

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    Public Class TechBook

        Inherits Book

        Public Overridable Shadows Function GetPrice() As Decimal

            Return 25.99

        End Function

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    End Class

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    Public Class DotNetTechBook

        Inherits TechBook

        Public Overrides Function GetPrice() As Decimal

            If MyBase.GetPrice = 25.99 Then

                Return 45.99

            Else

                Return 9.99

            End If

        End Function

    End Class

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End Module