Answer
The chronological age of the person is 50.
Work Step by Step
We have to calculate the value of the constant $k$ for $m=25$ and $c=20$.
Therefore,
$\begin{align}
& i=\frac{km}{c} \\
& 125=\frac{k\left( 25 \right)}{20} \\
& k\left( 25 \right)=125\left( 20 \right) \\
& k=\frac{2500}{25}
\end{align}$
Thus,
$k=100$
Now we can write this expression by using the value of the constant as $i=\frac{100m}{c}$.
Now according to the question, $i=80$ and $m=40$
$\begin{align}
& 80=\frac{100\left( 40 \right)}{c} \\
& c=\frac{4000}{80} \\
& c=50
\end{align}$
Thus, the chronological age of the person is 50.
