Write the equation which connects the statement above

Let $P$ represent the candidate's pressure.
Let $D$ represent the number of days left.
Let $T$ represent the topics covered.

"a candidate's pressure is directly proportional to the number of days left" means $P \propto D$.

"and inversely proportional to the topics covered" means $P \propto \frac{1}{T}$.

Combining $P \propto D$ and $P \propto \frac{1}{T}$ gives $P \propto \frac{D}{T}$.

To change a proportionality into an equation, we introduce a constant, let's call it $k$.