Answer
a. $41\%$, underestimates $2\%$
b. year $2030$
Work Step by Step
a. Given the formula $p=\frac{4x}{5}+25$ and year 2000 means $x=2000-1980=00$, we have $p=\frac{4(20)}{5}+25=41(\%)$. The bar graph gives a value of $43\%$; thus the model underestimates the data by $2\%$
b. Let $p=65(\%)$; we have $\frac{4x}{5}+25=65$ or $\frac{4x}{5}=40$ which gives $x=50$ and it is corresponds to year $1980+50=2030$
