Average Questions with Solutions | Set 1 (Q1 to Q10)

This set contains Average Questions with Solutions — Set 1 (Q1 to Q10) covering a mix of question types and difficulty levels — from basic to advanced — exactly as asked in real competitive exams.

Solutions are written in a simple, step-by-step notebook style for easy self-study and quick understanding. Each solution is broken down step by step so even the toughest question feels easy. These questions are hand-picked for students preparing for SSC CGL, SSC CHSL, CAT, Bank PO, Bank Clerk, UPSC CSAT, Railway RRB, AMCAT, eLitmus, TCS NQT and all campus placement aptitude tests. International students preparing for GRE, GMAT, SAT, ACT, MAT and all Numerical Reasoning Tests will find these equally useful.

✏️ Attempt each question on your own first — then check the solution below.

1. Find the average of first 67 numbers.

2. The average of 35 numbers is 380. If each of the number is divided by 19. Find the new average.

3. The average of 9 result is 60. If the average of first 5 result is 50 and the average of last 5 result is 70 then find the 5ᵗʰ result.

4. The average of 50 numbers is 45. The average of 50 numbers and 3 new number is 51. Then find the average of three new numbers.

5. The average salary of 30 workers in an office is Rs. 2400 per month. If the manager’s salary is added, the average becomes Rs. 2500 per month. Find the manager’s annual salary.

6. In a class there are 10 students at the age of 15 years. 15 students at the age of 10 years and 22 students of age 18 years. What is the average age of a student ?

7. A zoo has an average of 600 visitors on sunday and 390 visitors on other days. the average number of visitors per day in a month at 30 day beginning with sunday will be How many ?

8. The average age of 44 students in a class is 21 years. If the teacher’s age is included then average becomes 21 year 6 months. Find the age of teacher.

9. Find the average of following 12 numbers:
2, 10, 7, 9, 13, 12, 14, 18, 19, 5, 8, 3

10. Group A has 10 elements and their average is 5, Group B has 20 elements and their average is 8. If elements of these two groups are combined to form a third group C. Then find the average of Group C ?

1. Find the average of first 67 numbers.
Sol:
average = \(\frac{{\frac{{n(n + 1)}}{2}}}{n}\) = \(\frac{{n + 1}}{2}\) = \(\frac{{67 + 1}}{2}\) = 34      Answer

2. The average of 35 numbers is 380. If each of the number is divided by 19. Find the new average.
Sol:
New Average = \(\frac{{old\;average}}{{19}}\) = \(\frac{{380}}{{19}}\) = 20     Answer

3. The average of 9 result is 60. If the average of first 5 result is 50 and the average of last 5 result is 70 then find the 5ᵗʰ result.
Sol:
Method(1):
5ᵗʰ result = 5 × 50 + 5 × 70 – 9 × 60 = 60      Answer

4. The average of 50 numbers is 45. The average of 50 numbers and 3 new number is 51. Then find the average of three new numbers.
Sol:
Method(1):
Sum of three numbers = (50 + 3)×51 – 50×45
= 453
∴ average of three new numbers = \(\frac{{453}}{3}\) = 151      Answer

Method(2):
Increase in average = 51 – 45 = 6
A = 45
N = 50
 n = 3
∴ Average of new numbers = A + \(\left( {1 + \frac{N}{n}} \right)\).x
= 45 + \(\left( {1 + \frac{{50}}{3}} \right)\).6
= 151           Answer

Method(3):

5. The average salary of 30 workers in an office is Rs. 2400 per month. If the manager’s salary is added, the average becomes Rs. 2500 per month. Find the manager’s annual salary.
Sol:
Method(1):
Manager’s per month salary = (30 + 1)×2500 – 30×2400
= 5500
∴ annual salary of manager = 5500×12
= 66000 Rs.        Answer

Method(2):
N = 30
x = 2500 – 2400 = 100
A = 2400
n = 1
∴ per month salary of manager = A + \(\left( {1 + \frac{N}{n}} \right).x\)
= 2400 + \(\left( {1 + \frac{{30}}{1}} \right).100\)
 = 5500
∴ annual salary of manager = 5500 × 12
 = 66000 Rs.      Answer

Method(3):

6. In a class there are 10 students at the age of 15 years. 15 students at the age of 10 years and 22 students of age 18 years. What is the average age of a student ?
Sol:
Method(1):
Average age of a student = \(\frac{{10 \times 15 + 15 \times 10 + 22 \times 18}}{{10 + 15 + 22}}\)
= \(\frac{{696}}{{47}}\)
= \(14\frac{{38}}{{47}}\) years/student       Answer

Method(2):

7. A zoo has an average of 600 visitors on sunday and 390 visitors on other days. the average number of visitors per day in a month at 30 day beginning with sunday will be How many ?
Sol:
If the month starts with sunday then there will be 5 sunday in the month

8. The average age of 44 students in a class is 21 years. If the teacher’s age is included then average becomes 21 year 6 months. Find the age of teacher.
Sol:
Method(1):
Age of teacher = (44 + 1)21.5 – 44×21
= 43.5 year        Answer

Method(2):
A = 21
N = 44
n = 1
x = 0.5
age of teacher = A + \(\left( {1 + \frac{N}{1}} \right).x\)
= 21 + \(\left( {1 + \frac{{44}}{1}} \right)0.5\)
= 43.5 years        Answer

Method(3):

9. Find the average of following 12 numbers:
2, 10, 7, 9, 13, 12, 14, 18, 19, 5, 8, 3
Sol:
Method(1):

Average = \(\frac{{2 + 10 + 7 + 9 + 13 + 126 + 14 + 18 + 19 + 5 + 8 + 3}}{{12}}\)
= 10 Answer

Method(2):

10. Group A has 10 elements and their average is 5, Group B has 20 elements and their average is 8. If elements of these two groups are combined to form a third group C. Then find the average of Group C ?
Sol:
Method(1):

Average = \(\frac{{10 \times 5 + 20 \times 8}}{{10 + 20}}\) = 7    Answer

Method(2):
Using Alligation:

✅ Well done on completing Set 1!

Continue practising with Average Questions 11 to 20 → Set 2 or revisit the Average Concept Page to strengthen your formulas and tricks before moving ahead.

Consistent practice is the key to mastering average for SSC CGL, SSC CHSL, CAT, Bank PO, Bank Clerk, UPSC CSAT, Railway RRB, AMCAT, eLitmus, TCS NQT and international exams including GRE, GMAT, SAT, ACT, MAT and all Numerical Reasoning Tests. Want to understand the concept better? Read about Average on Wikipedia before attempting the next set.

This page is part of our complete series of average questions with solutions for competitive exams — covering every question type from basic to advanced so you can build speed, accuracy and confidence. Practising these questions regularly will also strengthen your core average concept before your exam day.