Answer
$f(x)=\displaystyle \frac{75}{1+1.5(0.980)^{-x}}$
.
Work Step by Step
In desmos.com, we add a table with variables $x_{1}$ and $y_{1}$ and enter the given points.
In the next free cell we enter
$y_{1}\sim N/(1+Ab^{-x_{1}})$
and the calculator returns
$N=75.3723:$ we round to $75$
$A=1.50166:$ we round to $1.5$
$b=0.979543:$ we round to $0.980$
$f(x)=\displaystyle \frac{75}{1+1.5(0.980)^{-x}}$
