Answer
9 days,
$(9.0, 0)$
Work Step by Step
Insert $P(x)=0$ and solve for x.
$0=95-30\log_{2}x\qquad.../+30\log_{2}x$
$30\log_{2}x=95\qquad.../\div 30$
$\displaystyle \log_{2}x=\frac{95}{30}\qquad...$apply $2^{(...)}$ to both sides
$ x=2^{95/30}\approx$8.97969638647$\approx 9.0$ days
After 9.0 days, all the students will have forgotten...
Since $P($9.0$)=0,$ the point on the graph is $(9.0, 0)$
