Although Hank is retired, he is an excellent handyman and often works part time on small projects for neighbors and friends. Last week his neighbor, Mike, offered to pay Hank $1,160 for minor repairs to his house. Hank completed the repairs in December of this year. Hank uses the cash method of accounting and is a calendar-year taxpayer. Compute Hank's gross income for this year from each of the following alternative transactions: a. Mike paid Hank $420 in cash in December of this year and promised to pay the remaining $740 with interest in three months.