Question

It costs 32000+2v^3 dollars to operate a cruise ship for an hour, where v is the velocity
of the ship measured in kilometres per hour. We want to operate the ship from Victoria
to Seattle, which are 120 kilometres apart. How long will it take us to do this trip if
we operate choosing the velocity that minimizes the total cost?

Warning: When you find the point you are looking for, make sure you actually explain
why it is a maximum/minimum of the function you are studying.
It costs 32000+2v^3 dollars to operate a cruise ship for an hour, where v is the velocity
of the ship measured in kilometres per hour. We want to operate the ship from Victoria
to Seattle, which are 120 kilometres apart. How long will it take us to do this trip if
we operate choosing the velocity that minimizes the total cost?

Warning: When you find the point you are looking for, make sure you actually explain
why it is a maximum/minimum of the function you are studying.
@Mathematics