Problem
In a circus, an average of 500 people pay $15 each to attend a performance. For each $2 increase in ticket price, the number of ticket buyers will decrease by 40. Find the number of dollars the price must be increased to achieve maximum revenue.
Solution
For this case we need to find a function for the attendance and other for the ticket price. and then multiply the two functions:
Price: 15 + 2x
Attendance: 500 -40x
x represent the number of $2 increases
And the revenue would be given by:
R = P* A
R = (15+2x)(500-40x)
R= 7500 - 600x +1000 x -80x^2
R= -80x^2 +400x +7 500
And if we take the derivate of this function we got:
R' = -160 x +400= 0
And solving for x we got:
x= 400/160= 2.5$ would be the increase
And the price would be:
P= 15 +2.5 *2= 20$ per ticket