Demand for residential electricity at 6:00 p.m. on the first Monday in October in Santa Theresa County is normally distributed with a mean of 4,905 MW (megawatts) and a standard deviation of 355 MW. Due to scheduled maintenance and unexpected system failures in a generating station, the utility can supply a maximum of 5,200 MW at that time. What is the probability that the utility will have to purchase electricity from other utilities or allow brownouts?