If You Must Pay $5000 in Taxes on a $25,000

If you must pay $5000 in taxes on a $25,000 taxable income and $7000 on a $30,000 taxable income,then the marginal tax rate on the additional $5000 of income is:

A) 40 percent and the average tax rate is about 23 percent at the $30,000 income level.
B) 50 percent and the average tax rate is about 40 percent at the $30,000 income level.
C) 40 percent and the average tax rate is about 25 percent at the $25,000 income level.
D) 30 percent,but average tax rates cannot be determined from the information given.
The marginal tax rate is the change in taxes divided by the change in income.In this case,the change in taxes was $2000 ,so the marginal tax rate was $2000/$5000 = 0.40.Average tax is $7000/$30,000 = 0.233.