The probability of not happening of an event is 0.63 . The probability of happening of that events is

Options

A. 0.36
B. `3.6`
C. `3.7`
D. `0.37`

Answer

To find the probability of an event happening when the probability of it not happening is given, we can use the following steps:

### Step-by-Step Solution:

1. **Understand the Relationship**:
The probability of an event happening (let's denote it as P(A)) and the probability of it not happening (denote it as P(A')) are related by the formula:
\[ P(A) + P(A') = 1 \]
Here, P(A') is the probability of the event not happening.

2. **Identify the Given Information**:
We are given that the probability of not happening of the event, P(A'), is 0.63.

3. **Use the Formula**:
To find the probability of the event happening, we can rearrange the formula:
\[ P(A) = 1 - P(A') \]

4. **Substitute the Known Value**:
Now, substitute the value of P(A'):
\[ P(A) = 1 - 0.63 \]

5. **Calculate the Result**:
Perform the subtraction:
\[ P(A) = 1 - 0.63 = 0.37 \]

6. **Conclusion**:
Therefore, the probability of the event happening is:
\[ P(A) = 0.37 \]

### Final Answer:
The probability of happening of that event is **0.37**.

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