Please just do it if you are 100% sure

"The cost in dollars of operating a jet-powered commercial airplane Co is given by the following equation Co = k*n*v^(3/2) where n is the trip length in miles, v is the velocity in miles per hour, and kis a constant of proportionality. It is known that at 412 miles per hour the cost of operation is $360 per mile. The cost of passengers' time in dollars equals $365,000 times the number of hours of travel. The airline company wants to minimize the total cost of a trip which is equal to the cost of operating plus the cost of passengers' time. At what velocity should the trip be planned to minimize the total cost? HINT: If you are finding this difficult to solve, arbitrarily choose a number of miles for the trip length, but as you solve it, you should be able to see that the optimal velocity does not depend on the value of n