20. when are equilibrium prices achieved?
a. when demand is greater than supply
b. when sellers break even
c. when supply equals demand
d. when supply is greater than demand

21. a company introduces a printer that does not require ink cartridges. as a result, the price of printers that use ink drops. what is another likely outcome?
a. the price of ink cartridges goes up.
b. the price of ink cartridges drops.
c. the demand for ink cartridges goes up.
d. the supply of ink cartridges drops.