NUMBER 54

54. Social Science According to the U.S. Census Bureau, the number of Americans (in thousands) who are expected to be over 100 years old in year x is approximated by the function where x = f(x) = .27x + 3.52x + 51.78, O corresponds to 2000 and the formula is valid through 2045. (a) Find a formula giving the rate of change in the num- ber of Americans over 100 years old. (b) What is the rate of change in the number of Americans expected to be over 100 years old in the year 2015? (c) Is the number of Americans expected to be over 100 years old in 2015 increasing or decreasing?