(13) [Averages versus margins: 12 pts] The following table shows U.S. first-class postal rates for letters as of September 2021. Complete the unshaded cells in the last two columns. Weight Price Average cost per Marginal cost per ounce ounce 0 ounces zero 1 ounce $0.58 $ $ 2 ounces $0.78 $ 3 ounces $0.98 $ Before answering the last three questions, review the slideshow on "Percent Changes." (14) [Computing percent changes: 9 pts] Suppose the price of gasoline is $3 in Houston and $5 in Los Angeles. a. Compute the percent difference using Houston as the base, to the nearest tenth of a % percentage point b. Compute the percent difference using Los Angeles as the base, to the nearest tenth % of a percentage point. c. Compute the percent difference using the midpoint formula, to the nearest tenth of % a percentage point. (15) [Percent changes of products: 6 pts] A firm's revenue is equal to price times quantity of output. Suppose price increases by 3 percent and quantity decreases by 2 percent. a. Will revenue increase or b. By about how much? decrease? % (16) [Percent changes of ratios: 6 pts] GDP per capita is equal to GDP divided by population. Suppose GDP increases by 4 percent and population increases by 1 percent. a. Will GDP per capita increase b. By about how much? or decrease? %