As of 2008, approximately what fraction of U.S. GDP does government purchases now represent?

Suppose when you are offered $8.00 per hour to work in the campus library, you choose not to work, but when you are offered $12.00 per hour, you accept a part-time position. Your behavior can best be explained by the fact that your supply of labor curve is:

A. upward-sloping. B. vertical. C. horizontal. D. downward-sloping.

The marginal income tax rate is equal to

A. the change in the tax payment divided by the change in income. B. the percent of total income that goes to taxes. C. the average tax payment divided by the total tax payment. D. the total tax payment divided by total income.