The Demand Function for a Certain Commodity Is $p ( x ) = 4 - \frac { 1 } { 30 } x$

Multiple Choice

The demand function for a certain commodity is $p ( x ) = 4 - \frac { 1 } { 30 } x$ Find the consumer surplus when the sales level is 30.

A) 90
B) 45
C) 15
D) 70
E) 30
F) 60
G) 20
H) 80