When A is a sure event, then what is P(A)?

Answer

To find the probability of event A when A is a sure event, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding a Sure Event**:
- A sure event is an event that is guaranteed to happen. In probability theory, this means that the event will occur with certainty.

2. **Definition of Probability**:
- The probability of any event is a measure of the likelihood that the event will occur. It is defined mathematically as:
\[ P(A) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} \]

3. **Maximum Probability**:
- The maximum probability of any event is 1. This means that if an event is certain to occur, its probability is 1.

4. **Applying to Event A**:
- Since event A is a sure event, it has a probability of occurring that is 100% or 1.

5. **Conclusion**:
- Therefore, we conclude that:
\[ P(A) = 1 \]

### Final Answer:
When A is a sure event, then \( P(A) = 1 \).

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