question_answer

If the mean of 10 observations is 20 and that of another 15 observations is 16, then the mean of 25 observations is ____.

A)  18                               

B)  18.2                

C)         17.6                

D)         17

Correct Answer: C

Solution :

Mean of 10 observations = 20 Mean of another 15 observations = 16 Total sum             = 200 + 240 = 440 Mean of 25 observations