Calculation of Composite Series Mean

To calculate the composite series mean, we need to first understand the concept of composite series. In this problem, we have three series 50, 60, and 90, and their respective means are 12, 15, and 20.

Composite Series:

A composite series is a series that is formed by combining two or more series. In this problem, we need to combine the three given series to form a composite series.

Steps to Calculate the Composite Series Mean:

1. Combine the three series:

We can combine the three series by writing them one below the other, as shown below:

50
60
90

2. Calculate the total sum of the composite series:

To calculate the total sum of the composite series, we need to add all the numbers in the series. Therefore,

Total sum of the composite series = 50 + 60 + 90 = 200

3. Calculate the total number of terms in the composite series:

To calculate the total number of terms in the composite series, we need to count the number of terms in each series and add them together. Therefore,

Total number of terms in the composite series = 3

4. Calculate the mean of the composite series:

The mean of the composite series can be calculated using the formula:

Mean = (Total sum of the composite series) / (Total number of terms in the composite series)

Therefore,

Mean of the composite series = 200 / 3 = 66.67

Therefore, the mean of the composite series is 66.67.

Conclusion:

The composite series mean is calculated by combining the given series and finding the mean of the combined series. In this problem, we combined the three series and found the mean of the composite series to be 66.67.