Isabella wishes to buy gasoline and have her car washed. She finds that if she buys 9 gallons of gasoline at $1.50 per gallon, the car wash costs $1, but if she buys 10 gallons of gasoline, the car wash is free. For Isabella, the marginal cost of the tenth gallon of gasoline is

$0.50

Explanation:

Marginal cost is the additional expense associated with consuming, selling, or producing one extra unit. For Susan, the marginal cost is the extra cost incurred by purchasing the 10th  gallon of gasoline.

To obtain the marginal cost:

The cost of 9 gallons plus cash wash

=(9 x $2) + $1.50= $19.50

cost of 10 gallons plus cash wash

=(10 x $2) cash wash is free= $ 20

The extra cost associated with the additional unit (marginal cost)

= $ 20- $ 19.50

=$0.50

answer: in the short-run firms will respond by raising the price of turkey.

explanation: initially the long-run equilibrium is at a price of $5 per pound of turkey and a quantity of 50 million pounds per year. now, when webmd claims that a protein found in turkey will increase your expected lifespan by 4 years. the consumers demand for turkey will increase at every price shifting the demand curve to the right from d1 to d2. while, there will be no change in the supply curve in the short-run as it is not possible for producers to adjust supply so quickly. as a result the new equilibrium will occur at a higher price and a higher quantity of turkey.

thus, in the short run firms will respond by increasing the price of turkey, selling more quantity at a higher price and earning economic profits.