If out of 10 selected students for an examination, 3 were of 20 years, age, 4 or 21 and 3 of 22 years, the average age of the group is

Options

A. 22 years
B. 21 years
C. 21.5 years
D. 20 years

Answer

To find the average age of the group of selected students, we can follow these steps:

### Step 1: Identify the number of students and their ages
We have:
- 3 students aged 20 years
- 4 students aged 21 years
- 3 students aged 22 years

### Step 2: Calculate the total age for each group
- For the 3 students aged 20 years:
\[ 3 \times 20 = 60 \text{ years} \]

- For the 4 students aged 21 years:
\[ 4 \times 21 = 84 \text{ years} \]

- For the 3 students aged 22 years:
\[ 3 \times 22 = 66 \text{ years} \]

### Step 3: Find the total age of all students
Now, we add the total ages calculated above:
\[ 60 + 84 + 66 = 210 \text{ years} \]

### Step 4: Calculate the average age
To find the average age, we divide the total age by the number of students:
\[ \text{Average Age} = \frac{\text{Total Age}}{\text{Number of Students}} = \frac{210}{10} = 21 \text{ years} \]

### Conclusion
The average age of the group is **21 years**.

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