12. You are given the following information:

Quantity demanded of donuts is described by the equation Qd = 25 - 4P.

Quantity supplied of donuts is described by the equation Qs = 4 + 3P.

Using this information, calculate thequantity supplied and thequantity demanded of donuts if the price is:

a. $2.00;

b. $3.00. What is interesting about this particular price?

c. $4.00.

13. a. Explain the difference between achange in demand and achange in quantity

demanded.

b. List the different factors that cause the demand curve to shift and the supply

curve to shift.