Question 259462
a charter company will provide for a fare of $60 each for 20 or fewer passengers.
 for each passenger in excess of 20, the fare is decreased $2 per person for everyone what number of passengers will produce the greatest revenue for the company 
:
Let x = no. of passengers greater than 20
:
Revenue = no. of passengers * price per passenger
r = (20+x)*(60-2x)
FOIL
r = 1200 - 40x + 60x - 2x^2
A quadratic equation
-2x^2 + 20x + 1200 = 0
:
We can find x that gives the max revenue by finding the axis of symmetry; x = -b/(2a)
In this equation a = -2; b = 20
x = {{{(-20)/(2*-2)}}}
x = {{{(-20)/(-4)}}}
x = +5
;
We can say 25 passengers will give max revenue