public virtual double CalculateNetPayableTax() { double netTaxableIncome = CalculateGrossIncome(TaxPayer) - GetChapter6Deductions(); return(TaxSlabs.GetInstance().ComputeTax(netTaxableIncome, TaxPayer) - (AnnualSalary.ProfessionalTax + AnnualSalary.TaxDedeuctedAtSource)); }