A. [tex]R(x)=(360-2x)(90+x)\\R(x)=32400+360x-180x-2x^2\\R(x)=-2x^2+180x+32400[/tex]
B. [tex]R(x)=-2x^2+180x+32400\\R'(x)=-4x+180=0\\180=4x\\45=x\\\\R(45)=-2(45)^2+180(45)+32400\\R(45)=-2(2025)+8100+32400\\R(45)=-4050+40500\\R(45)=36450\\\\90+45\\135[/tex]
135 passengers will maximize the revenue at $36,450.