The data in the table above give two points on the demand curve for pizza. Using the midpoint method, when the price of a pizza falls from $10 to $9, what is the percentage change in the quantity demanded?

Which of the following is a positive externality of consumption?

a. inoculations against a disease reduce the likelihood of transmitting it to others b. phosphates from laundry detergents c. litter from fast-food containers d. ozone depletion from the production of fast-food containers e. the greenhouse effect

During the 1970s, real shocks to the U.S. economy caused:

a. an increase in both aggregate demand and aggregate supply. b. an increase in both the price level and the unemployment rate. c. a leftward shift of the Phillips curve. d. a decline in inflation but higher unemployment. e. a decline in both the price level and the unemployment rate.