Bob is the president of Jackson Corp. and owns 40% of its stock. Jackson Corp. is organized as an S corporation. During 2020, Jackson Corp. has a loss of $160,000. At the beginning of 2020, Bob's amount at-risk in Jackson Corp. is $30,000. In 2021, Jackson Corp. has a taxable income of $50,000. Determine Bob's (1) deduction amount and (2) the ending balance of amount at-risk for 2020 and 2021, respectively. Also, (3) what is the purpose of the at risk-rules?