Question

The mean of 9 numbers is 50. One of the numbers is wrongly recorded as 63 instead of 36. What is the correct mean?

• A. 47
• B. 48
• C. 49
• D. 50

Hint:

Corrected mean = Wrong total − Wrong value + Correct value, then divide by count.

Answer 1

The Correct Option is A

Concept: Correct mean = (Correct total sum) / Number of observations. Explanation: Wrong mean = 50 Number of values = 9 Wrong total sum: \[ 9 \times 50 = 450 \] The number was recorded as 63 instead of 36. So, subtract wrong value and add correct value: \[ Correct\ sum = 450 - 63 + 36 = 423 \] Correct mean: \[ \frac{423}{9} = 47 \]