Aptitude Problems on Average – Tips and Tricks to Solve in IBPS PO and Clerk Exams with Examples
Introduction by Rahul Sir Hello Aspirants, I am Rahul Sir, and over the years I have trained thousands of banking aspirants preparing for IBPS PO, IBPS Clerk, SBI PO, SBI Clerk, RRB, and other competitive examinations. Among the most frequently asked topics in the Quantitative Aptitude section is Average. Many students consider it an easy chapter, yet they often lose marks because of calculation mistakes, incorrect assumptions, or lack of shortcut techniques. Average forms the foundation for several advanced topics such as Partnership, Profit and Loss, Mixture and Alligation, Data Interpretation, and Time & Work. Therefore, mastering averages not only helps you solve direct questions but also improves your overall quantitative aptitude. In this article, I will share practical tips, shortcut methods, exam-oriented tricks, and solved examples that can significantly improve your speed and accuracy in banking examinations. If practiced regularly, these techniques can help you solve average-based questions within seconds during the examination. Let us begin by understanding the concept and then move toward advanced tricks used by banking toppers. 1. Understanding the Basic Concept of Average Average represents a central value that reflects the overall performance of a group of numbers. The basic formula is: Average = Sum of Observations ÷ Number of Observations For example: The marks obtained by five students are: 40, 50, 60, 70, 80 Sum = 300 Average = 300 ÷ 5 = 60 In banking exams, questions are rarely this straightforward. Examiners test your understanding by introducing changes, replacements, additions, or exclusions in the dataset. Averages help simplify large amounts of data into one representative value. Instead of remembering every individual observation, you can understand the general trend through a single figure. Important points: Example: Average of 8 numbers is 25. Total sum = 25 × 8 = 200 This simple relationship between average and total sum forms the basis of most exam questions. Students should memorize this relationship because many questions can be solved without actually calculating individual values. The quicker you convert averages into totals, the faster you can solve banking aptitude questions. 2. The Golden Formula: Total = Average × Number One of the most important tricks in average problems is converting average into total. Formula: Total Sum = Average × Number of Terms Example: Average salary of 20 employees is ₹25,000. Total salary = 20 × 25,000 = ₹5,00,000 This approach saves significant time. Example: Average age of 15 students is 18 years. Total age = 15 × 18 = 270 years. If one student leaves and another joins, we compare the totals instead of calculating individual ages. Banking examinations frequently use this concept. Shortcut: Whenever you see average, immediately think about total sum. Questions involving additions, replacements, increases, decreases, and missing values become much easier when solved using total values. Example: Average of 10 numbers is 30. Total = 300 One number is replaced by 50 and average becomes 32. New Total = 320 Difference = 20 Thus replaced number = 50 − 20 = 30 Such tricks save several calculation steps. Practice converting every average question into total sum form before attempting detailed calculations. This habit alone can improve your speed dramatically. 3. Finding Missing Numbers Using Average Questions involving missing values are extremely common in IBPS examinations. Example: Average of five numbers is 24. Four numbers are 20, 22, 25, and 28. Find the fifth number. Solution: Total sum = 24 × 5 = 120 Sum of known numbers: 20 + 22 + 25 + 28 = 95 Missing number = 120 − 95 = 25 Shortcut Approach: Calculate total first. Subtract known values. The remainder is the missing value. Another Example: Average of seven numbers is 40. Six numbers total 220. Total required = 40 × 7 = 280 Missing number = 280 − 220 = 60 Such questions become extremely easy once you focus on total sums rather than averages directly. Exam Tip: Never calculate averages repeatedly. Convert to total, solve, and then reconvert if necessary. This technique reduces mistakes and improves accuracy. 4. Addition and Removal of Members Many banking exam questions involve adding or removing people from a group. Example: Average age of 10 students is 15 years. A new student joins. Average becomes 16 years. Find the age of the new student. Solution: Original total = 10 × 15 = 150 New total = 11 × 16 = 176 New student’s age = 176 − 150 = 26 years Example of Removal: Average age of 12 employees is 30 years. One employee leaves. Average becomes 29 years. Original total = 360 New total = 11 × 29 = 319 Age of removed employee = 360 − 319 = 41 years This concept appears frequently in IBPS PO and Clerk examinations. Always compare old total and new total. Never attempt long calculations. 5. Replacement Problems Made Easy Replacement questions are among the most scoring questions in banking exams. Example: Average age of 20 students is 18 years. One student is replaced. Average increases by 1 year. Find the age difference. Solution: Increase in total = 20 × 1 = 20 years Thus new student is 20 years older than the student who left. Shortcut Formula: Difference in age = Change in Average × Number of Members This direct formula eliminates lengthy calculations. Example: Average salary of 30 employees decreases by ₹500 after replacement. Difference = 30 × 500 = ₹15,000 Thus replaced employee’s salary exceeded the new employee’s salary by ₹15,000. Practice this formula extensively because it appears regularly in banking examinations. 6. Weighted Average Concept Weighted average combines groups having different averages. Formula: Weighted Average = (Total Sum of Groups) ÷ (Total Members) Example: Average marks of 20 boys = 60 Average marks of 30 girls = 70 Total marks: Boys = 20 × 60 = 1200 Girls = 30 × 70 = 2100 Combined average: 3300 ÷ 50 = 66 Many Data Interpretation questions use weighted averages. Students should focus on totals first and then compute the final average.









