21. Think about the demand for the three game consoles: Xbox, PS3, and Wii. Explain the effect of the following events on the demand for Xbox games and the quantity of Xbox games demanded, other things remaining the same.

a. The price of an Xbox falls.

b. The prices of a PS3 and a Wii fall.

c. The number of people writing and producing Xbox games increases.

d. Consumers’ incomes increase.

e. Programmers who write code for Xbox games become more costly to hire.

f. The expected future price of an Xbox game falls. g. A new game console that is a close substitute for Xbox comes onto the market.