The equation for a demand curve has been estimated to be:
Q=100-10P+0.5Y
Where Q is quantity, P is price and Y is income. Assume that P=7 and Y=50.
a.) At a price 7, what is the price elasticity?
b.) At an income level of 50, what is the income elasticity?
c.) Now assume that income is 70. What is the price elasticity at P=8?