While Kimberly Brown, an experienced truck driver, is bored waiting in a queue in the port of Long Beach, she remembers one of her old ideas. During the last years, she has been taken notes about her work routine and found that her weekly profit is somehow dependent on the waiting time spent on queues during that week. As she has already traveled to many facilities and ports in her country area, she has a good estimation of how much queueing time she is expected to wait and how much money she earns on each trip. She is no longer willing to spend so much time in queues, but she understands that, in order to make money, it is necessary to bear with some queues weekly. She then remembers the relation she found, with her historical data, for the weekly profit in dollars and the weekly queueing waiting time in hours (x): profit = -32 x2 +521x +(-149) Based on her wide knowledge of facilities' historical waiting times, what is the amount of queue waiting time in hours that Kimberly should be willing to experience to maximize her profit for next week?