In a class of 30 students, the average weight of boys is 20kg and the average weight of the girls is 25kg. The fraction of boys out of the total students of the class is :

Options

A. 44320
B. 44352
C. 44289
D. Data insufficient

Answer

To solve the problem, we need to find the fraction of boys out of the total students in a class of 30 students, given the average weights of boys and girls.

### Step-by-Step Solution:

1. **Define Variables**:
Let the number of boys be \( B \) and the number of girls be \( G \).
We know that the total number of students is:
\[ B + G = 30 \]

2. **Use Average Weights**:
The average weight of boys is given as 20 kg, and the average weight of girls is given as 25 kg. Therefore, the total weight of boys can be expressed as:
\[ \text{Total weight of boys} = 20B \]
Similarly, the total weight of girls can be expressed as:
\[ \text{Total weight of girls} = 25G \]

3. **Calculate Total Weight**:
The total weight of all students in the class can be expressed as:
\[ \text{Total weight} = 20B + 25G \]

4. **Average Weight of Class**:
The average weight of the entire class can be calculated as:
\[ \text{Average weight} = \frac{\text{Total weight}}{\text{Total students}} = \frac{20B + 25G}{30} \]

5. **Set Up the Equation**:
We can express the average weight of the class in another way. However, since we do not have the average weight of the entire class, we cannot directly calculate \( B \) or \( G \). Therefore, we cannot find the fraction of boys without additional information about the average weight of the class or the number of boys or girls.

6. **Conclusion**:
Since we do not have enough information to determine the exact values of \( B \) and \( G \), we conclude that the data is insufficient to find the fraction of boys out of the total students.

### Final Answer:
The fraction of boys out of the total students of the class is **data insufficient**.