The formula to calculate the percent delay (PD) is:
\[ PD = \left( \frac{Tac - Tal}{Tal} \right) \times 100 \]
Where:
Let's say the actual time is 120 minutes and the allocated time is 100 minutes. Using the formula:
\[ PD = \left( \frac{120 - 100}{100} \right) \times 100 \]
We get:
\[ PD = \left( \frac{20}{100} \right) \times 100 = 20 \]
So, the percent delay (\( PD \)) is 20%.