Answer: Elasticity of demand mesures the responsivness of quantit demanded to a change in the price of the product. It is calculated as,

a. P1 = $160 , P2= $140, Q1=80, Q2= 120
e=

b. P1 = $140 , P2= $160, Q1=120, Q2= 80
e=

c. Mid-point method is given by

So, we have

d. P1=$40, P2= $20, Q1= 320, Q2= 360

e. P1=$20, P2= $40, Q1= 360, Q2= 320

f. [tex] e= \frac{360 - 320}{360+320/2} * \frac{40+20/2}{20-40}
=\frac{40}{340} * \frac{30}{-20}
= - 0.17