Chapter 9, Problem 27E

The Social Security Administration uses a linear growth model to estimate life expectancy in the United States. The model uses the explicit formula $L_N=66.17+0.96N$ where $L_N$ is the life expectancy of a person born in the year $1995+\mathrm{N}$ (i.e., $\mathrm{N}=0$ corresponds to 1995 as the year of birth $\mathrm{N}=1$ corresponds to 1996 as the year of birth, and so on). (Source: Social Security Administration, wwwsocialsecurity.fov.)

a. Assuming the model continues to work indefinitely, estimate the life expectancy of a person born in 2012.

b. Assuming the model continues to work indefinitely, what year will you have to be born so that your life expectancy is 90?