A group of 30 employees of Cadre A has a mean age of 27. A different group of 70 employees of Cadre B has a mean age of 23. What is the mean age of the employees of the two groups together?

Question: A group of 30 employees of Cadre A has a mean age of 27. A different group of 70 employees of Cadre B has a mean age of 23. What is the mean age of the employees of the two groups together?

Solution:
• Cadre A has a mean age = 27
- Total employees = 30
- Total age = 27×30 = 810 years

On the other hand,
• Cadre B has a mean age = 23
- Total employees = 70
- Total age = 1610 years

• From both the A and B cadre groups,
- Total employees = 100
- Total age = 2420 years
Now, Mean or Average = 2420/100 = 24.2 years.