The following table gives the total U.S. population, in millions, for selected years from 1990 and projected

Question:

The following table gives the total U.S. population, in millions, for selected years from 1990 and projected to 2050.
(a) Find a logarithmic function model for the data. Use x as the number of years past 1950 and report the model with four significant digit coefficients.
(b) Use the model to find the expected U.S. population in 2018.
(c) Use the reported model to find the x-value when the total U.S. population is predicted to reach 400 million.