If the market price is $40 in a perfectly competitive market, the marginal revenue from selling the fifth unit is

The natural level of real GDP is that level of

A) real GDP at which the price level will continue increasing. B) nominal GDP at which the price level will remain constant. C) real GDP at which there is no tendency for inflation to accelerate or decelerate. D) Nominal real GDP at which the price level will continue to decrease.

The marginal income tax rate applies to

A) all income earned by a family. B) the income in the highest tax bracket reached. C) the income of the highest income U.S. taxpayers. D) the income received by people above the national average.