The mean score of 25 observations is 80 and the mean score of another 55 observations is 60. Determine the mean score of the whole set of observations.

The mean of a set of 20 observations is 8 and of another set of 30 observations is 10. The mean of combined set is

The mean of 20 observations is 30. If the mean of first 15 observations is 32, find the mean of last 5 observations.

The mean of 20 observations is 30. If the mean of first 15 observations is 32, find the mean of last 5 observations.

The mean of a set of 12 observations is 10 and another set of 8 observations is 12. The mean of combined set is ______.

The mean of a set of 20 observations is 8 an another set of 30 observations is 10. The mean of combined set is ________.

The mean of 5 observations is 60, the mean of 10 observations is 30 and the mean of 15 observations is 20. The mean of all the 30 observations is (a)20quad (b) 25quad (c) 30 (d) 40

The mean of 25 observations is 36. If the mean of the first 13 observations is 32 and that of the last 13 observations is 39 then the 13^(th) observation is :

Out of 250 observations, the first 100 observations have mean 5 and the average of the remaining 150 observations is 25/3 What is the average of the whole group of observations ?

The mean of first three observations is 15 and the mean of next two observation is 20. The mean of all five observations is-

Mean of 35 observations is 75 .The mean of first 18 observations is 70 and the mean of last 18 observations is 80 .Then the 18^(th ) observation is