According to recent data the survival function for life after 62 is approximately given by upper s left parenthesis x right parenthesis equals 1 minus 0.051 x minus 0.077 x squared where x is measured in decades. this function gives the probability that an individual who reaches the age of 62 will live at least x decades (10x years) longer.

The ages of personnel in the accounting department of a large company are normally distributed with a standard deviation of 7 years. there is a 0.02275 probability that the age of any randomly chosen person in the department is less than 22 and 0.15866 probabilty that the age of any randomly chosen person is greater than 43. what is the mean of this distribution?