The Demand Equation for a Certain Brand of Fax Machine

Multiple Choice

The demand equation for a certain brand of fax machine is 4x + p - 1,550 = 0, where x is the quantity demanded per week and p is the unit price in dollars. The supply equation is 3x - 4p + 2,400 = 0, where x is the quantity the supplier will make available in the market when the unit price is p dollars. Find the equilibrium quantity and the equilibrium price for the fax machines.

A) equilibrium quantity 200 units; equilibrium price $750
B) equilibrium quantity 200 units; equilibrium price $850
C) equilibrium quantity 90 units; equilibrium price $850
D) equilibrium quantity 90 units; equilibrium price $750