# 11.4.1. Calculating Probability

In a school celebration for excellently-performing students, the probability that Minister of Education attends is 0.65, the probability that the vice principal of the school attends is 0.51, and the probability that both attend is 0.3. Find the probability that at least one of them attends.

- A0.86
- B0.21
- C0.35
- D0.14

### Example

In a school celebration for excellently-performing students, the probability that Minister of Education attends is 0.65, the probability that the vice principal of the school attends is 0.51, and the probability that both attend is 0.3. Find the probability that at least one of them attends.

### Solution

In this case, event

If

First, use this fact to determine

Thus, the probability that at least one of them attends the school celebration is 0.86.