Change ASP.Net GridView cell value based on average value in C# and VB.Net

Please help how can i do this based on the average score if it is less than 50 then the status should indicated failed as indicated in the display below using gridview.

thanks.

Public Class StudentSearch
    Inherits System.Web.UI.Page
    Dim conString As String = ConfigurationManager.ConnectionStrings("INTERVIEWSConnectionString").ConnectionString
 
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
 
    End Sub
    Private Function ExecuteQuery(ByVal cmd As SqlCommand, ByVal action As String) As DataTable
        'Dim conString As String = conString
        Using con As New SqlConnection(conString)
            cmd.Connection = con
            Select Case action
                Case "SELECT"
                    Using sda As New SqlDataAdapter()
                        sda.SelectCommand = cmd
                        Using dt As New DataTable()
                            sda.Fill(dt)
                            Return dt
                        End Using
                    End Using
                Case "UPDATE"
                    con.Open()
                    cmd.ExecuteReader()
                    con.Close()
                    Exit Select
            End Select
            Return Nothing
        End Using
    End Function
 
    Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        If CheckBox1.Checked = True Then
            Dim cmd As New SqlCommand("SELECT Account,upper(Name) as Name,Class,Stream,Category,Intake,Eng,Maths,Sst,Science, ([maths]+[eng])/2 AS Average,([maths]+[eng])AS TotalMarks
            FROM student
                    WHERE (((student.Class)=@c) AND ((student.Intake)=@it)) and  (status IS NULL)
                        ORDER BY class,student.Name, [maths]+[eng]/2 DESC;")
            cmd.Parameters.AddWithValue("@c", DropDownList2.SelectedItem.Text)
            cmd.Parameters.AddWithValue("@it", DropDownList1.SelectedItem.Text)
            Label2.Text = Nothing
            Studentgrid.DataSource = Me.ExecuteQuery(cmd, "SELECT")
            Studentgrid.DataBind()
            'Required for jQuery DataTables to work.
            Studentgrid.UseAccessibleHeader = True
            Studentgrid.HeaderRow.TableSection = TableRowSection.TableHeader
        Else
            Dim cmd As New SqlCommand("SELECT Account as Admno,upper(Name) as Name,Class,Stream,Category,Intake,Eng,Maths,([maths]+[eng])/2 AS Average,([maths]+[eng])AS TotalMarks
            FROM student
                    WHERE (((student.Class)=@c) AND ((student.Intake)=@it)) and  (status IS NULL)
                        ORDER BY class,student.Name, [maths]+[eng]/2 DESC;")
            cmd.Parameters.AddWithValue("@c", DropDownList2.SelectedItem.Text)
            cmd.Parameters.AddWithValue("@it", DropDownList1.SelectedItem.Text)
            Label2.Text = Nothing
            Studentgrid.DataSource = Me.ExecuteQuery(cmd, "SELECT")
            Studentgrid.DataBind()
            'Required for jQuery DataTables to work.
            Studentgrid.UseAccessibleHeader = True
            If Studentgrid.Rows.Count = 0 Then
                Response.Write("<script>alert('No Records yet for this Class');</script>") 
                Exit Sub
            Else
                Studentgrid.HeaderRow.TableSection = TableRowSection.TableHeader
            End If 
        End If
    End Sub
 
    Protected Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Dim named As String = DropDownList2.SelectedValue
        Dim intake As String = DropDownList1.SelectedValue
        Dim point As Boolean = CheckBox2.Checked
        Response.Redirect(String.Format("~/Reports/DisplayReport.aspx?class={0}&intake={1}&point={2}", named, intake, point))
    End Sub
End Class