John owed $$10,000$ in taxes on taxable income of $$40,000.$ If John earns an additional $$1,000,$ he will pay an additional $$280.$ Therefore:

Multiple choice question.

his marginal tax rate will increase to $29\%$

he will be at the $30\%$ average tax rate after he earns the additional $$1,000$

his average tax rate is about $25\%$

his average tax rate is $28\%$