Answer
$P(t)=\displaystyle \frac{42}{1+0.17(0.80)^{-t}}$
Work Step by Step
(We use desmos.com for the calculations/graph below.)
Logistic Model form: $\displaystyle \quad R=\frac{N}{1+Ab^{-t}}$
1. create a table with variable names $t$ and $P$ (R for research articles) and enter the data.
2. in the next free cell, enter
$P\sim N/(1+Ab^{-t})$
The calculator returns $\left\{\begin{array}{l}
N=42\\
A=0.17\\
b=0.80
\end{array}\right.$
(rounded to 2 significant figures.)
$P(t)=\displaystyle \frac{42}{1+0.17(0.80)^{-t}}$
