Answer
$9.0$ days, point $(9.0,0)$
Work Step by Step
Step 1. Given the model equation $P(x) = 95 - 30 log_2( x)$, let $P(x)=0$ percent; we have $95 - 30 log_2( x)=0$
Step 2. Solving the above equation, we have $log_2(x)=\frac{19}{6}$ and $x=2^{19/6}\approx9.0$ days.
Step 3. The equation can also be solved by using the given graph; locate $0$ vertically and find the x-coordinate of the point on the curve. We have $x\approx9.0$ days and the point is $(9.0,0)$
