Should Arthur get to work in IT as a Software developer, at Sydney, he aim to earn approximately $175,000 per year. If he earns a NET INCOME OF: $175,000, he qualifies for the $120,001-180,000 bracket so his tax rate will be 37% after every dollar over $29,467. 

That means automatic tax rate is 29,467

The additional tax is 

 $125,183, per year, and $10,432 per month.