# 11.4.1. Calculating Probability

In a school graduation celebration, the probability that the governor attends is 0.82, and the probability that the general education director attends is 0.45. If the probability that both of them attend is 0.31, find the probability that both of them will NOT attend.

- A0.04
- B0.14
- C0.51
- D0.96

### Example

In a school graduation celebration, the probability that the governor attends is 0.82, and the probability that the general education director attends is 0.45. If the probability that both of them attend is 0.31, find the probability that both of them will NOT attend.

### Solution

In this case, event

Since

De Morgan's First Law states that