Answer:
25
Step-by-step explanation:
Let number of passengers greater than 20 be 'x'
thus,
the total number of passengers = 20 + x
and,
the total cost = $60 - $2x
now,
The revenue function will become as:
R(x) = cost × Number of passengers
or
R(x) = ( 60 - 2x ) × ( 20 + x )
or
R(x) = 1200 + 60x - 40x - 2x²
or
R(x) = 1200 + 20x - 2x²
Now,
for point of maxima, differentiating w.r.t 'x'
we have
R'(x) = 20 - 4x = 0
or
x = 5
Hence,
the ideal number of passenger is 20 + x = 20 + 5 = 25