Calculation of AI's gross income for 2017:
Cash received during the year 2017 $280,000
Less: Amount collected for the services provided in the year 2016 - $40,000
Add: Accounts receivable for services rendered in 2017 $60,000
AI's gross income for 2017 = (280000-40000+60000) =$300,000
Hence, AI's gross income for 2017 is $300,000