SSC CGL (Prelims) General: Averages questions with solutions

Q1. A student's average score in 12 exams is 72. If his highest score is excluded, the average becomes 70. What is his highest score?

1. 92
2. 94
3. 96
4. 98

Answer: 94

The total score in 12 exams is $12 \times 72 = 864$. After excluding the highest score, the total of 11 exams is $11 \times 70 = 770$. So the highest score is $864 - 770 = 94$.

Q2. Table: Test Scores (out of 100) Student X: 82, 78, 85 Student Y: 88, 86, 90 Which student had a higher average score?

1. Student X
2. Student Y
3. Both are equal
4. Cannot be determined

Answer: Student Y

Student X's average is $(82+78+85)/3 = 245/3$. Student Y's average is $(88+86+90)/3 = 264/3 = 88$. Since 88 is greater, Student Y has the higher average.

Q3. The average age of 30 students in a class is 15 years. When a new student is admitted, the average increases by 0.5 years. What is the age of the new student?

1. 30.5
2. 23.5
3. 24.5
4. 35.5

Answer: 30.5

The original total age is 30 × 15 = 450 years. After admission, the average becomes 15.5 for 31 students, so the new total is 31 × 15.5 = 480.5 years. The new student's age is 480.5 − 450 = 30.5 years.

Q4. The monthly average salary of 6 employees and one manager is ₹18,000. If the manager earns ₹30,000, what is the average salary of the 6 employees?

1. ₹ 16,800
2. ₹ 17,000
3. ₹ 16,000
4. ₹ 15,600

Answer: ₹ 16,000

The total salary of 7 people is 7 × 18,000 = ₹1,26,000. Subtracting the manager’s salary gives ₹96,000 for the 6 employees. Their average salary is ₹96,000 ÷ 6 = ₹16,000.

Q5. A factory has 100 workers, of whom 40% are women. The average monthly salary of women is ₹50,000, while men earn ₹60,000 on average. What is the overall average monthly salary of the workforce (in ₹000s)?

1. 56
2. 56.5
3. 57
4. 57.5

Answer: 56

There are 40 women and 60 men. Total salary = 40 × 50,000 + 60 × 60,000 = ₹56,00,000. Dividing by 100 workers gives an average of ₹56,000, i.e. 56 in ₹000s.

Q6. The average score of 25 students in a test is 68. The top 5 scorers had an average of 80, and the lowest 5 had an average of 50. What is the average of the remaining 15 students?

1. 70
2. 68
3. 72
4. 66

Answer: 70

The total score of 25 students is $25 \times 68 = 1700$. The top 5 scored $5 \times 80 = 400$ and the lowest 5 scored $5 \times 50 = 250$, so the remaining 15 scored $1700 - 400 - 250 = 1050$. Their average is $1050/15 = 70$.

Q7. A student scored 80% in one subject and 60% in another. Both subjects have equal maximum marks. What is the overall percentage?

1. 70%
2. 72%
3. 68%
4. 75%

Answer: 70%

When two subjects have equal maximum marks, the overall percentage is the average of the two percentages. So, $(80 + 60)/2 = 70\%$.

Q8. The average of three numbers is 35. The first number is 20% more than the second, and the third is 20% less than the second. What is the second number?

1. 35
2. 36
3. 37.5
4. 40

Answer: 35

Let the second number be x. Then the first number is 1.2x and the third number is 0.8x. Their average is 35, so (1.2x + x + 0.8x)/3 = 35, giving x = 35.

Q9. If the average of ten numbers is 50 and the average of the first six numbers is 45, what is the average of the last four numbers?

1. 55
2. 62.5
3. 60
4. 57.5

Answer: 57.5

The sum of ten numbers is 10 × 50 = 500. The sum of the first six numbers is 6 × 45 = 270, so the sum of the last four numbers is 500 - 270 = 230. Their average is 230/4 = 57.5.