Averages Formula
Averages formulas and a topic-wise mock test for quantitative aptitude placement exams like TCS NQT, Infosys, and Wipro. Revise, then practice.
Key Averages Formulas
Average Fundamentals - Central Tendency
Average (arithmetic mean) represents the typical value of a set of numbers. Calculated by summing all values and dividing by the count.
- Average = Sum of observations / Number of observations
- Sum = Average × Number of observations
- Adding New Value: New average = (n×a + x) / (n+1)
- Removing Value: New average = (n×a - x) / (n-1)
- Example: Average of 5 numbers=20, Sum=100. Add 25 → New avg=(100+25)/6=20.83
Weighted Average - Importance-Based Calculations
Weighted average gives different importance to different values based on their significance.
- Weighted Average = (n1×a1 + n2×a2 + ...) / (n1 + n2 + ...)
- If weights are equal, weighted average = simple average
- Age Problems: Total age = Average age × Number of people
- Example: 10 students (avg 60) + 15 students (avg 70) → Weighted avg = 1650/25 = 66
Advanced Average Problems
Practical applications of average concepts.
- Example 1: Avg of 5=20, Sum=100. Add 25 → New avg=125/6=20.83
- Example 2: 10 students (60) + 15 students (70) → Weighted avg=1650/25=66
- Example 3: Avg of 6=18, replace one number: New sum=108-old+24, New avg=new sum/6
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