If the tax structure is as follows Income Bracket 0-10,000 10,001-40,000 40,001-100,000 100,001 and above Percentage Rate 5% 10% 20% 30% a) If the income of Ali for the current year is 80,000, and the taxable income is 70,000. Compute the tax liability, marginal tax rate, average tax rate, and effective tax rate b) If the income (total and taxable) of Mona, for the current year, is 400,000. Compute the tax liability, marginal tax rate, average tax rate, and effective tax rate