The market for 40 lb. bags of pine bark mulch (sold at John's shop) is described by the following functions:

Question

p = -.3q + 66
p = 1.3q - 30
where p is the price per unit and q is the number of bags bought and sold.
a) Which of the functions above is the demand function? Explain. b) Find the equilibrium price and quantity in this market. q = ______________
p = ______________
c) Rewrite the demand function with quantity as the dependent variable.
d) If the price is $40, is there a surplus or a shortage? How much? Explain.