Answer
$2.8$ days, point $(2.8,50)$
Work Step by Step
Step 1. Given the model equation $P(x) = 95 - 30 log_2( x)$, letting $P(x)=50$ percent, we have $95 - 30 log_2( x)=50$
Step 2. Solving the above equation, we have $log_2(x)=\frac{3}{2}$ and $x=2^{3/2}=2\sqrt 2\approx2.8$ days.
Step 3. The equation can also be solved by using the given graph; locate $50$ vertically and find the x-coordinate of the point on the curve. We have $x\approx2.8$ days and the point is $(2.8,50)$
