How much taxable income should each of the following taxpayers report?

a. Kimo builds custom surfboards. During the current year, his total revenues are $90,000, and he incurs $30,000 in expenses. Included in the $30,000 is a $10,000 payment to Kimo's five-year-old son for services as an assistant.

b. Manu gives hula lessons at a local bar. During the current year, she receives $9,000 in salary and $8,000 in tips. In addition, she engages in illegal behavior, for which she receives $10,000.