Help with a Formula please

Maybe try using the User Defined Function (UDF) below:

Function GetCleansed(Cleansed As Integer, Total As Integer, PercentTarget As Double)

    Dim x As Integer
    
    For x = 1 To 10000
        If Cleansed / Total >= PercentTarget Then
            GetCleansed = "Target Met"
            Exit Function
        ElseIf (Cleansed + x) / (Total + x) > PercentTarget Then
            GetCleansed = Cleansed + x
            Exit Function
        End If
    Next x
    GetCleansed = "Large Number...."
End Function

If you're unfamiliar with UDFs then please take a look at this link for some additional information:

https://www.vertex42.com/blog/excel-formulas/custom-user-defined-functions.html