Answer
a. $10\ hrs$, underestimates by 1 hour.
b. $11\ hrs$.
Work Step by Step
a. Using the given function $f(x) = 1.8 ln (x) + 3.42$, with $x=2010-1964=46$, we have $f(46) = 1.8 ln (46) + 3.42\approx10\ hrs$. The bar graph gives a value of $11$ hours; thus the function value underestimates the number by 1 hour.
b. For year $2025$, we have $x=2025-1964=61$ and $f(61) = 1.8 ln (61) + 3.42\approx11\ hrs$.
