question_answer

The mean of 13 observations is 14. If the mean of the first 7 observations is 16 and that of the last 7 observations is 12, then the 7th observation is ____.

A)  12                   

B)         14                   

C)  16                   

D)         18                   

Correct Answer: B

Solution :

Mean of first 7 observations = 16 Sum of first 7 observations Mean of last 7 observations = 12 Sum of last 7 observations Now, mean of 13 observations = 14 Sum of 13 observations 7th observation