In a class of 180 students, 45% are girls and the remaining are boys. If the average of the girl's marks is 54 and that of the boys is 46, what is the average of the whole class ?

Options

A. 49.8
B. 49.7
C. 49.6
D. 49.5

Answer

To find the average marks of the whole class, we can follow these steps:

### Step 1: Calculate the number of girls and boys in the class.
- Total number of students = 180
- Percentage of girls = 45%
- Number of girls = 45% of 180 = (45/100) * 180 = 81
- Number of boys = Total students - Number of girls = 180 - 81 = 99

### Step 2: Calculate the total marks obtained by girls and boys.
- Average marks of girls = 54
- Total marks obtained by girls = Average marks * Number of girls = 54 * 81 = 4374

- Average marks of boys = 46
- Total marks obtained by boys = Average marks * Number of boys = 46 * 99 = 4554

### Step 3: Calculate the total marks of the whole class.
- Total marks of the class = Total marks of girls + Total marks of boys = 4374 + 4554 = 8928

### Step 4: Calculate the average marks of the whole class.
- Average marks of the whole class = Total marks of the class / Total number of students = 8928 / 180 = 49.6

### Final Answer:
The average marks of the whole class is **49.6**.

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