The demand curve for the new computer game, Rock and Roll Trivia, is given as follows
Q= 200 - 5P - .1Pc - .5Pd + .2A -I
where:
P is the price of the game
Pc is the price of a computer
Pd is the price of a diskette
A is the level of advertising
Q is the level of income
Suppose P=10, Pc=100, Pd=2, A=5 and I=50. What is the price elasticity of demand?