The probability that it is Friday and a student is absent, is 0.03. Since, there are 5 school days in a week, the probability that it is Friday is 0.2. What is the probability that a student is absent, given that today is Friday?

Answer

To solve the problem, we need to find the probability that a student is absent given that today is Friday. This can be expressed using conditional probability.

### Step-by-step Solution:

1. **Identify the Given Probabilities:**
- Let \( A \) be the event that a student is absent.
- Let \( F \) be the event that today is Friday.
- We are given:
- \( P(A \cap F) = 0.03 \) (the probability that it is Friday and the student is absent)
- \( P(F) = 0.2 \) (the probability that it is Friday)

2. **Use the Formula for Conditional Probability:**
The formula for conditional probability is given by:
\[ P(A | F) = \frac{P(A \cap F)}{P(F)} \]
where \( P(A | F) \) is the probability that a student is absent given that today is Friday.

3. **Substitute the Known Values:**
Now, we can substitute the known values into the formula:
\[ P(A | F) = \frac{P(A \cap F)}{P(F)} = \frac{0.03}{0.2} \]

4. **Calculate the Probability:**
Now we perform the division:
\[ P(A | F) = \frac{0.03}{0.2} = 0.15 \]

5. **Conclusion:**
Therefore, the probability that a student is absent given that today is Friday is \( 0.15 \).

### Final Answer:
\[ P(A | F) = 0.15 \]