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

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

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

c) Determine the incremental tax rate.

d) Determine the marginal tax rate this year.