Question

The mean weight of 9 students is 25 kg. If one more student is joined in the group the mean is unaltered, then the weight of the 10th student is

• A. 25 kg
  
• B. 24 kg
  
• C. 26 kg
  
• D. 23 kg
  

Answer 1

The correct option is A 25 kg

Formula used:

$Arithmeticmean=\frac{Sumofgivennumbers}{Totalnumbers}$

Apply the above formula, we get the sum of weights of the 9 students = $25\times 9=225$ kg

If one more student is joined in the group, then total number of students is 10, and the mean isn 25.

The sum of weights of the 10 students is $25\times 10=250$ kg

The weight of the tenth student is $250-225=25$ kg