Wang Li, a solicitor in criminal law, lives in Sydney. In the year 2020-21, Wang earns income from two sources. He receives income of $72,000 from his employment in the office of public prosecution, however subsequently quits this position in December 2020, and commences a private legal service business "Just Justice" as a sole trader from 1 January 2021. The business earns a revenue of $55,000 by 30 June 2021. Wang purchases a computer ($2,200) and a printer ($1,100) on 1 July 2020, which he initially uses for the public prosecution work, and later in the "Just Justice" business. Required: Advise Wang on the income tax and GST consequences on receipts and expenses for the income year 2020-21. Please support your answer with relevant legislation and cases (where relevant, the amounts are GST-inclusive)