Mohan found that the average of 4 numbers is 25. On rechecking, Sohan noticed that the number 15 had been wrongly taken as 51. What is the correct average?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 16
A wrong entry changes the total: take out the wrong number, put in the right one, and divide the corrected total by the count again.
Total used by Mohan \(=4\times25=100\)
Correct total \(=100-51+15=64\)
\(\displaystyle \text{Correct average}=\frac{64}{4}=16\)
The correct average is 16.