The formula to calculate the CPU Busy Time (B) is:
\[ B = T - I \]
Where:
Let's say the total time (T) is 100 seconds and the idle time (I) is 30 seconds. Using the formula:
\[ B = 100 - 30 \]
We get:
\[ B = 70 \text{ seconds} \]
So, the CPU busy time is 70 seconds.