Dalam suatu kelas terdapat 20 murid laki-laki dan 15 murid 

perempuan. Rata-rata nilai ulangan Kimia di kelas tersebut 

adalah 70. Setelah melihat hasil tersebut, guru Kimia 

memberikan kesempatan kepada 4 murid, dengan nilai 

masing-masing 42, 44, 48, dan 50, untuk melakukan 

remedial dan nilai rata-rata peserta remedial menjadi naik 

15 poin.

To solve this problem, we need to analyze the effect of the remedial exam on the class's overall chemistry test average.

### **Given:**
1. The class has **20 male** and **15 female** students, so the total number of students is:
   \[
   n = 20 + 15 = 35 \text{ students}
   \]

2. The **average score** of the class is 70.

3. The teacher allows **4 students** who scored **42, 44, 48, and 50** to retake the exam, and after the remedial, each of their scores increases by **15 points**.

### **Step 1: Calculate the Initial Total Score of the Class**

The initial total score of all the students in the class is calculated using the formula:
\[
\text{Total Score} = \text{Average} \times \text{Number of Students} = 70 \times 35 = 2450
\]

### **Step 2: Calculate the Score Increase Due to the Remedial**

The original scores of the 4 students are:
\[
42, 44, 48, 50
\]

Their scores after increasing by 15 points each:
\[
42 + 15 = 57, \quad 44 + 15 = 59, \quad 48 + 15 = 63, \quad 50 + 15 = 65
\]

### **Step 3: Calculate the Total Increase in Scores**

The increase in total score due to the remedial is:
\[
(57 - 42) + (59 - 44) + (63 - 48) + (65 - 50) = 15 + 15 + 15 + 15 = 60
\]

### **Step 4: Calculate the New Total Score of the Class**

The new total score after remedial becomes:
\[
\text{New Total Score} = 2450 + 60 = 2510
\]

### **Step 5: Calculate the New Average Score of the Class**

The new average score of the class is:
\[
\text{New Average} = \frac{\text{New Total Score}}{\text{Number of Students}} = \frac{2510}{35} \approx 71.71
\]

So, after the remedial, the new average score of the entire class is approximately **71.71**.

### Summary:
After the 4 students took the remedial test and improved their scores by 15 points each, the average score of the entire class increased from 70 to approximately 71.71.

---

### Would you like details or have any questions?  
Here are 5 follow-up questions:

1. How would the average change if more students took the remedial?
2. How would the result change if only 3 students were allowed to retake the exam?
3. What would happen to the average if one of the remedial students improved by more than 15 points?
4. Can you calculate the class's new standard deviation after the score changes?
5. How would you calculate the effect on the average if the entire class was allowed a remedial exam?

**Tip:** Always check how individual changes in data points (like scores) affect the overall average, as small changes can sometimes lead to significant differences.

Explore how a remedial exam affects the average score in a class of 35 students with specific score improvements. Learn about statistics and arithmetic mean calculations with practical examples.

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