# 11.4.1. Calculating Probability

A class contains 25 boys and 13 girls, where 5 boys and 4 girls wear glasses. If one student was selected randomly from this class, find the probability that the student does NOT wear glasses.

- A
- B
- C
- D

### Example

A class contains 25 boys and 13 girls, where 5 boys and 4 girls wear glasses. If one student was selected randomly from this class, find the probability that the student does NOT wear glasses.

### Solution

The probability of event

The probability of event

The notation

Since

Since

Thus, the probability of selecting a student who does not wear glasses is