If A and B are two events such that `AsubeB`, then P(B|A) is equal to

Options

A. 0
B. 1
C. `1/2`
D. `1/3`

Answer

To solve the problem, we need to find \( P(B|A) \) given that \( A \subseteq B \).

### Step-by-Step Solution:

1. **Understanding the Definition of Conditional Probability**:
The conditional probability \( P(B|A) \) is defined as:
\[ P(B|A) = \frac{P(A \cap B)}{P(A)} \]

2. **Identifying \( A \cap B \)**:
Since \( A \) is a subset of \( B \) (i.e., \( A \subseteq B \)), the intersection of \( A \) and \( B \) is simply \( A \):
\[ A \cap B = A \]

3. **Substituting into the Conditional Probability Formula**:
Now we can substitute \( A \cap B \) with \( A \) in the conditional probability formula:
\[ P(B|A) = \frac{P(A)}{P(A)} \]

4. **Simplifying the Expression**:
Since \( P(A) \) is not zero, we can simplify this to:
\[ P(B|A) = 1 \]

### Final Answer:
Thus, \( P(B|A) = 1 \).

---