Suppose the market demand for air purifiers is Qd = 180/p and market supply is p given by Qs = 3p.

Note that market demand is not a straight line. This is completely fine. What matters is that it is downward sloping.

(a) Calculate the equilibrium price and quantity of air purifiers

(b) Graph the market. Be sure to label all curves, axes, and intersections.

(c) Suppose existing firms in the market for air purifiers are making economic profits, and this induces new firms to enter the market leading to a shift in the market supply curve. If the new supply curve is given by Qs = 5p, calculate the new equilibrium price and quantity.

(d) Add the new supply curve and the new equilibrium price and quantities to the same graph you drew in part (b).