CA Foundation · Quantitative Aptitude · Measures of Central Tendency and Dispersion
Firm A has 40 employees with a mean monthly salary of ₹30,000. Firm B has 60 employees with a mean monthly salary of ₹25,000. What is the combined mean monthly salary of all employees of both firms?
The combined mean salary is ₹27,000. Each firm's mean is weighted by its headcount: (40×30,000 + 60×25,000)/100 = 27,00,000/100. Simply averaging the two means gives ₹27,500, which ignores that Firm B is larger.
- A₹27,000Correct
- B₹27,500
- C₹28,000
- D₹26,000
Explanation
Total salary of A = 40 × 30,000 = ₹12,00,000 and of B = 60 × 25,000 = ₹15,00,000. The combined total is ₹27,00,000 for 100 employees, so the mean is ₹27,000. The value ₹27,500 is the simple average of the two means and ignores the different group sizes.
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