QUESTION 1: Tax system design

Because of the pandemic, low-income earners are entitled to a coronavirus supplement cash payment depending on their income level (in addition to any Centrelink payments, which we will ignore). The higher the income, the more the cash payment is reduced. Here are two tables that show the coronavirus supplement and reduction thresholds:

Your maximum fortnightly Your circumstances Single. no children. younger than 18. and live at your parent's home $31 3.30 Single. no children, younger than 1 3. living away from your parent's home to $53040 study. train or look for work Single. no children. 18 or older and live at parent's home $367.00 Single. no children. 18 or older and need to live away from parent's home $530.40 Single. with children $679.00 A couple. with no children $530.40 A couple. with children $577.40 Amount your payment Amount your payment Maximum income reduces by if you earn reduces by if you earn before your Your situation between $452-$542 per more than $542 per payment reduces fortnight fortnight to $0 Single, no children, 50 cents for each dollar $43.50 plus 60 cents for younger than 18, and live $996.50 over $452 each dollar over $542 at your parent's home Single, no children, 18 or 50 cents for each dollar $43.50 plus 60 cents for older and live at your $1,086.34 over $452 each dollar over $542 parent's home Single or in a couple, no children, and need to live 50 cents for each dollar $43.50 plus 60 cents for $1,362.67 away from your parent's over $452 each dollar over $542 home Member of a couple with 50 cents for each dollar $43.50 plus 60 cents for $1,442.17 children over $452 each dollar over $542 50 cents for each dollar $43.50 plus 60 cents for Single with children $1,614.00 over $452 each dollar over $542Resident tax rates 2021-22 Taxable income Tax on this income 0 - $18,200 Nil $18,201 - $45,000 19 cents for each $1 over $18,200 $45,001 - $120,000 $5,092 plus 32.5 cents for each $1 over $45,000 $120,001 - $180,000 $29,467 plus 37 cents for each $1 over $120,000 $180,001 and over $51,667 plus 45 cents for each $1 over $180,000