Question

The mean age of 50 persons was found to be 32 years. Later it was detected that the age 28 was wrongly noted as 35, the age 57 was wrongly noted as 30 and the age 60 was wrongly noted as 32. Then the correct mean age is

• A. 28
• B. 33
• C. 31
• D. 32.4

Answer 1

The correct option is C

31

Total age of 50 persons noted = $50\times 32=1600$
Correct total age of 50 persons = $50\times 32-35+28-30+57-32+60=1650$
$\therefore Mean=\frac{1650}{50}=33$
Hence (c) is the correct answer.