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To solve this question, we need to apply the combined average (rata-rata gabungan) formula. Here’s a step-by-step breakdown of how to proceed:

### Known Data:
- Number of male students \( n_1 = 15 \)
- Number of female students \( n_2 = 10 \)
- Combined average weight for the class \( R = 56 \)
- Average weight of male students \( R_1 = 58 \)

### Goal:
- We are asked to find the average weight of the female students \( R_2 \).

### Formula for Combined Average:
The formula to calculate the combined average is:

\[
R = \frac{n_1 R_1 + n_2 R_2}{n_1 + n_2}
\]

Where:
- \( R \) is the overall average (56),
- \( n_1 \) and \( n_2 \) are the numbers of male and female students,
- \( R_1 \) is the average weight of male students (58),
- \( R_2 \) is the unknown average weight of female students.

### Substituting the values:

\[
56 = \frac{15 \times 58 + 10 \times R_2}{15 + 10}
\]

\[
56 = \frac{870 + 10 \times R_2}{25}
\]

Multiplying both sides by 25:

\[
1400 = 870 + 10 \times R_2
\]

Now, solving for \( R_2 \):

\[
10 \times R_2 = 1400 - 870
\]

\[
10 \times R_2 = 530
\]

\[
R_2 = \frac{530}{10} = 53
\]

So, the average weight of the female students is **53**.

### Correct Answer:
The correct option is **E (53)**.

Would you like more details, or do you have any further questions?

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Here are 5 related questions for further practice:
1. How would the result change if there were more female students than male students?
2. Can you derive the combined average if both \( R_1 \) and \( R_2 \) are unknown?
3. What is the impact on the average if a student with an extreme weight is added to the group?
4. How does the combined average formula change if you include weights of more than two groups?
5. What if the total number of students is unknown? Can we still solve for the average?

**Tip:** Always double-check units when applying formulas that involve averages to ensure consistency.

Diketahui jumlah siswa laki-laki dikelas Silat adalah 15 orang dan siswa perempuan 10. Rata-rata berat badan siswa laki-laki dan perempuan dikelas tersebut adalah 56. Jika rata-rata berat badan laki-laki adalah 58, berapakah rata-rata berat badan perempuan di kelas Silat?

Learn how to calculate the average weight of female students using the combined average formula in a class of 15 male students and 10 female students. Given the average weight of male students is 58 and the overall class average is 56, this problem breaks down key concepts in averages and algebra. Suitable for Grades 7-9.

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