The bar graph shows the percentage of U.S. college freshmen with an average grade of A in high school.
(GRAPH CAN NOT COPY)
The data displayed by the bar graph can be described by the mathematical model
$$p=\frac{4 x}{5}+25$$
where $x$ is the number of years after 1980 and $p$ is the percentage of U.S. college freshmen who had an average grade of A in high school. Use this information
Refer to the mathematical model and the bar graph at the bottom of the previous column.
a. According to the formula, in $2000,$ what percentage of U.S. college freshmen had an average grade of A in high school? Does this underestimate or overestimate the percent displayed by the bar graph? By how much?
b. If trends shown by the formula continue, project when $65 \%$ of U.S. college freshmen will have had an average grade of $\mathrm{A}$ in high school.