TenTec in Sevierville, Tennessee, makes commercial and amateur radio equipment, including receivers, transceivers, antenna tuners, linear amplifiers, and so on. Their taxable income last year was \($720,000.\) They have established a new line of electronic equipment that is on sale this year and that is expected to add another \($140,000\) to taxable income.

a. Determine the effective (average) tax rate on all of last year’s taxable income.

b. Determine the effective (average) tax rate on all of this year’s taxable income.

c. Determine the incremental tax rate.

d. Determine the marginal tax rate this year.