Suppose that the US demand for maple syrup in thousands of g

Suppose that the U.S. demand for maple syrup in thousands of gallons per year, is Qd= 6000 –30 P. What is the elasticity of demand at a price of $75 per gallon?(Hint: find the relevant quantity at the price of $75 using the demand function.)

Solution

Qd= 6000 –30 P

P=75

Qd= 6000-30(75) = 6000-2250 = 3750

elasticity,Ed= -(dQd/dP)*(P/Qd)

                   = -(-30) *(75/3750)= 0.6