03 Maximum Revenue for Tour Bus of 80 Seats

Original cost per seat
          = 28,000 ÷ 80 = P350

Additional cost per seat due to P1,000 increase
          = 1,000 ÷ 80 = P12.5
 

Let x = number of P1,000 additional charges
Additional cost per seat = 12.5x
Cost per seat = 350 + 12.5x
Number of seats sold = 80 - 2x
 

Revenue, R = cost per seat × number of seats sold
$R = (350 + 12.5x)(80 - 2x)$

$R = 28,000 + 300x - 25x^2$

$\dfrac{dR}{dx} = 300 - 50x = 0$

$x = 6$
 

For Maximum Revenue

Cost per seat = 350 + 12.5(6) = P425
Number of seats sold = 80 - 2(6) = 68
Maximum Revenue = 425(68) = P28,900   ←   [ C ]   answer