Question

The average of 15 observations was found as 35. Later it was found that while calculating, two observations were read as 23 and 14 instead of 33 and 24. The correct average is?

• A. 36.33
• B. 35.80
• C. 37.21
• D. 40.33

Hint:

Read the question carefully and eliminate the clearly incorrect options first.

Answer 1

The Correct Option is A

The originally calculated (but incorrect) total for the 15 observations was \(15 \times 35 = 525\). Since 23 was mistakenly recorded instead of the actual value of 33, and 14 instead of 24, the correction needed is \(525 - 23 - 14 + 33 + 24 = 545\).
The correct average is then \(545/15 = 36.33\), matching option 1.