Latesha, a single taxpayer, had the following income and deductions for the tax year 2017:

INCOME:	Salary	$ 80
	Business Income	25
	Interest income from bonds	10
	Tax-exempt bond interest	5
	TOTAL INCOME	120
DEDUCTIONS:	Business expenses	$ 9
	Itemized deductions	20
	Personal exemption	4
	TOTAL DEDUCTIONS	33

a. Compute Latesha’s taxable income and federal tax liability for 2017 (round to dollars).
b. Compute Latesha’s marginal, average, and effective tax rates.
c. For tax planning purposes, which of the three rates in Part b is the most important?