Consider the example of the three$-$step airport security. The first step, verifying ID and

boarding pass, takes $30$ seconds per passenger. The second step, searching the passenger for metal objects using a metal detector, takes $10$ seconds per passenger. The third step, running the carry$-$on luggage through an X$-$ray machine, takes $60$ seconds per passenger. Assume that there are many customers waiting in the process and that each of the three employees gets paid $$15$ per hour. What is the cycle time?