Answer:
total tax liability = $6,000
marginal tax rate = 20%
Step-by-step explanation:
total tax liability = ($4,000 x 10%) + [($50,000 - $40,000) x 20%] = $4,000 + $2,000 = $6,000
The marginal tax rate is the tax rate applicable to an additional dollar of income. Since the $50,000 income falls into the second bracket, the marginal tax rate is 20%.