Math elasticity of demand word problem below.

Question

A study of demand for air travel in Australia found that the demand (q) for discount air travel from Sydney to Melbourne depends on the airfare according to the equation q=55.2-.022p, where p is price in dollars. Find the elasticity when the price (p) is $166.10. Round your answer to three decimals

Answer 1

Elasticity of demand E(p) = - pf'(p)/F(p) = -p(-0.022)/(55.2 - 0.022p) = 0.022p/(55.2 - 0.022p)

E(166.10) = 0.022/(55.2 - 0.022·166.10) = 0.0004268 = 4.268·10^-4.