An unmarried taxpayer with no dependents expects an adjusted gross income of $70,000 in a given year. His nonbusiness deductions are expected to be $6000. (a) What will his federal income tax be? (b) He is considering an additional activity expected to increase his adjusted gross income. If this increase should be $16,000 and there should be no change in nonbusiness deductions or exemptions, what will be the increase in his federal income tax?