Average Concepts for Bank Exams
Average Mastery (Professional Level)
Average is one of the easiest and most scoring topics in bank exams. It is widely used in data interpretation, time & work, and mixture problems.
1. Basic Formula
Average = Total Sum / Number of Items
Example: Average of 2, 4, 6 = (2+4+6)/3 = 4
2. Shortcut Concept
If all values are equal, average is that value.
Example: 10, 10, 10 → Average = 10
3. Assumed Mean Method
Choose a base value to simplify calculation.
Example: Values: 48, 50, 52 Assume mean = 50 Deviations: -2, 0, +2 → Sum = 0 Average = 50
Used to reduce calculation time
4. Average Change Concept
If one value changes, average changes proportionally.
Example: 5 numbers average = 20 Total = 100 If one number increases by 5 → new total = 105 → average = 21
5. Reverse Average Trick
Total = Average × Number
Example: Average = 25, items = 4 → Total = 100
6. Combined Average
Combined Average = (Sum1 + Sum2) / (n1 + n2)
Example:
Group1 avg = 10 (5 items → sum = 50)
Group2 avg = 20 (5 items → sum = 100)
Combined avg = 150/10 = 15
7. Important Tricks
- Use assumed mean to simplify
- Convert average into total quickly
- Track increase/decrease carefully
- Avoid long addition
Speed Strategy
- Use reverse method
- Apply assumed mean
- Focus on deviation method
- Practice mixed problems
Practice Questions
1. Average of 10, 20, 30 = ?
2. Total if average 25 and items 8 = ?
3. New average if one value increases by 10 (5 items)?
4. Combined average of 2 groups (given avg)?
Smart Methods Reduce Calculation Time
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