Chapter 10.1, Problem 55E

SAT Scores by Income The following bar graph shows U.S. math SAT scores as a function of household income:⁸

These data can be modeled by

$S\left(x\right)=573-133{\left(0.987\right)}^x,$ where $S\left(x\right)$ is the average math SAT score of students whose household income is x thousand dollars per year. Numerically estimate $\underset{x\to +\infty }{\lim S}\left(x\right),$ and interpret the answer.