Question

The A.M. of 30 students is 42. Among them, two students got zero marks. Then A.M. of the remaining students is

• A. 40
• B. 45
• C. 50
• D. 55

Answer 1

The Correct Option is B

To solve the problem, we need to find the arithmetic mean (A.M.) of the remaining students after excluding two students who scored zero marks. Here's the step-by-step solution:

Step 1: Understand the given information.
The arithmetic mean (A.M.) of the scores of 30 students is 42. This means the total sum of their scores is:

\[ \text{Total sum of scores} = \text{A.M.} \times \text{Number of students} = 42 \times 30 = 1260 \]

Step 2: Account for the two students who scored zero.
Since two students scored zero, their contribution to the total sum is zero. Therefore, the total sum of the scores of the remaining 28 students is still 1260.

Step 3: Calculate the A.M. of the remaining 28 students.
The arithmetic mean of the remaining 28 students is given by:

\[ \text{A.M. of remaining students} = \frac{\text{Total sum of scores of remaining students}}{\text{Number of remaining students}} = \frac{1260}{28} \]

Step 4: Perform the division.
Calculate \( \frac{1260}{28} \):

\[ \frac{1260}{28} = 45 \]

Final Answer:
The arithmetic mean of the remaining students is \(45\).