t : 1800 1820 1840 1860 1880 1900 1910 1920 1930

P : 7.24 9.64 17.07 23.2 50.2 76.2 92.2 106.0 123.2

t : 1940 1950 1960 1970 1980 1990 2000 2010

P : 132.2 151.3 179.3 203.3 226.5 248.8 281.4 308.75

a) Plot ln(P) vs. t , and calculate a value of growth rate (r) from the slope of the plot.

b) Extrapolate values for the population of the United States in the years 2025 and 2050.

c) It has been estimated that the net growth rate calculated in part(a) is due almost totally to immigration. If net immigration (and thus the overall growth rate) were reduced by 50%, what would the population be in the year 2050?