There are 13 girls and 15 boys in a line . If one students is chosen at random , then the probability that he is not a boy is .

Options

A. `(1)/(15)`
B. `(13)/(28)`
C. `(1)/(18)`
D. `(1)/(13)`

Answer

To solve the problem, we need to find the probability that a randomly chosen student from a line of 13 girls and 15 boys is not a boy. Here’s the step-by-step solution:

### Step 1: Determine the number of girls and boys
- We have 13 girls and 15 boys.

### Step 2: Calculate the total number of students
- Total number of students = Number of girls + Number of boys
- Total number of students = 13 + 15 = 28

### Step 3: Identify the favorable outcomes
- The favorable outcomes for the event "not a boy" are the girls.
- Number of favorable outcomes (girls) = 13

### Step 4: Calculate the probability
- Probability (P) is given by the formula:
\[ P(\text{not a boy}) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} \]
- Substituting the values:
\[ P(\text{not a boy}) = \frac{13}{28} \]

### Step 5: Conclusion
- Therefore, the probability that a randomly chosen student is not a boy is \(\frac{13}{28}\).

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