Average
SSC GD Exam Preparation - Quantitative Aptitude
🔹 1. What is Average?
Average means the equal distribution of a total quantity among a set of items or persons.
Average = Sum of values / Number of values
🔹 2. Important Concepts
✔ Sum = Average × Number of items
This is the most fundamental relationship in average problems.
✔ If one value is replaced:
New Sum = Old Sum - Removed Value + Added Value
✔ If the average increases or decreases:
Increase in Total = Change in Average × Number of Items
🔹 3. Key Formulas
Formula 1 — Simple Average
A = (x₁ + x₂ + x₃ + … + xₙ) / n
Formula 2 — Weighted Total
Total = Average × Number
Formula 3 — Finding Missing Number
Missing Value = Total Required - Total of Known Values
🔹 4. Examples
Example 1
Numbers: 5, 7, 9
Average = (5 + 7 + 9)/3 = 7
Example 2
Average of 6 numbers = 12
Total = 6 × 12 = 72
Example 3
Average of 5 numbers is 20. If one number (30) is removed:
New sum = 100 – 30 = 70
New average = 70/4 =
17.5
🧠 Practice Section: 15 Average Questions (With Answers)
Test your average concepts with these SSC GD level practice questions. Click on "View Answer" to check your understanding.
Q1. Find the average of 12, 18, 24, 30.
View Answer
Sum = 84 → Average = 84/4 = 21
Q2. Average of 5 numbers is 26. Find their sum.
View Answer
Sum = 26 × 5 = 130
Q3. The sum of 6 numbers is 144. Find average.
View Answer
144/6 = 24
Q4. Average of 3 numbers is 40. Two numbers are 35 and 45. Find the third number.
View Answer
Total = 40×3 = 120, Third = 120 − (35 + 45) = 40
Q5. Average of 10 numbers is 15. If one number 25 is added, find new average.
View Answer
Old total = 150, New total = 175, New average = 175/11 = 15.9
Q6. Average age of 8 students is 14. One new student joins and the new average becomes 15. Find age of new student.
View Answer
Old total = 112, New total = 135, New student = 135 − 112 = 23
Q7. The average marks of 7 students is 60. If one student leaves and the new average becomes 58, find the marks of the student who left.
View Answer
Old total = 420, New total = 58×6 = 348, Left student = 420 − 348 = 72
Q8. Find the average of first 5 even numbers.
View Answer
Numbers: 2,4,6,8,10 → Total=30 → Avg= 6
Q9. Average of 4 numbers is 50. If a fifth number 70 is included, find new average.
View Answer
Old total = 200, New total = 270, Average = 270/5 = 54
Q10. Average of 6 numbers is 32. If one number 20 is removed, find new average.
View Answer
Old total = 192, New total = 172, New avg = 172/5 = 34.4
Q11. The average of x & 20 is 30. Find x.
View Answer
(x + 20)/2 = 30, x + 20 = 60, x = 40
Q12. Average of 9 numbers is 28. If a new number 55 is added, find new average.
View Answer
Old total = 252, New total = 307, New avg = 307/10 = 30.7
Q13. Average of 4 numbers is 18. If each number is increased by 2, find new average.
View Answer
Increase in average = 2, New average = 20
Q14. Average weight of 12 boys is 50 kg. If teacher's weight is added, average becomes 52 kg. Find the weight of teacher.
View Answer
Old total = 600, New total = 52×13 = 676, Teacher = 676 − 600 = 76 kg
Q15. Average of 5 consecutive numbers is 27. Find the smallest number.
View Answer
For consecutive numbers → middle = average = 27, Smallest = 27−2 = 25
✅ SSC GD Exam Strategy
🟢 Remember Sum = Average × Number for quick calculations
🟢 Practice addition/removal of numbers from a set
🟢 Master finding missing numbers using total sum
🟢 Learn to handle consecutive number problems
🟢 Time yourself - aim for 30-45 seconds per average question
You've completed Average Concepts!
SSC GD Tip: Average problems are fundamental in the quantitative section. Focus on mastering the relationship between sum, average, and number of items. Remember that when numbers are added or removed, you need to adjust the total sum first before calculating the new average. Practice consecutive number problems and missing number scenarios as they frequently appear in exams. Regular practice with previous year SSC GD questions will build your speed and accuracy in solving average problems efficiently.
Master Average Problems for SSC GD Exam!
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