The class mark of the class 90-120 is

Options

A. 90
B. 105
C. 11
D. 120

Answer

To find the class mark of the class interval 90-120, we can follow these steps:

### Step 1: Identify the lower and upper limits of the class interval.
- The lower limit is 90.
- The upper limit is 120.

### Step 2: Use the formula for the class mark.
- The formula for the class mark (M) is given by:
\[ M = \frac{\text{Lower Limit} + \text{Upper Limit}}{2} \]

### Step 3: Substitute the values into the formula.
- Substitute the lower limit (90) and upper limit (120) into the formula:
\[ M = \frac{90 + 120}{2} \]

### Step 4: Calculate the sum of the lower and upper limits.
- Calculate \(90 + 120\):
\[ 90 + 120 = 210 \]

### Step 5: Divide the sum by 2 to find the class mark.
- Now divide 210 by 2:
\[ M = \frac{210}{2} = 105 \]

### Final Answer:
- The class mark of the class interval 90-120 is **105**.

---