Quality control engineers create acceptable boundaries for variability within the processes they monitor. They determine that the acceptable boundary for a certain heat exchange process at a gasoline refinery must be set such that under normal operating conditions the threshold would be exceeded only 1% of the time. Under normal operating conditions, the process varies according to a normal distribution, with mean temperature of 231°C and standard deviation of 2.5°C. What upper temperature should they set so that the process will normally exceed the temperature 0.51% of the time?