SSC CGL Preparation – Day 5

MCQ Set: Average (Day 5 Practice)

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1. The average of five numbers is 27. If one number is excluded, the average becomes 25. What is the excluded number?
A) 32
B) 35
C) 37
D) 40

Answer: ✅ C) 37
Solution:
Total of 5 numbers = 27 × 5 = 135
Total of remaining 4 = 25 × 4 = 100
Excluded number = 135 − 100 = 37

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2. The average of first 20 even numbers is:
A) 20
B) 21
C) 22
D) 21.5

Answer: ✅ B) 21
Solution:
First 20 even numbers: 2, 4, 6, …, 40
Average = (First + Last) / 2 = (2 + 40) / 2 = 21

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3. A cricketer has a batting average of 45 in 10 innings. In the next innings, he scores 75 runs. What is his new average?
A) 48
B) 50
C) 47.73
D) 46.5

Answer: ✅ C) 47.73
Solution:
Old total = 10 × 45 = 450
New total = 450 + 75 = 525
New average = 525 / 11 = 47.73

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4. The average age of 8 men is 32 years. A new man joins the group, and the average becomes 31. What is the age of the new man?
A) 23
B) 25
C) 27
D) 24

Answer: ✅ A) 23
Solution:
Old total = 8 × 32 = 256
New total = 9 × 31 = 279
New man’s age = 279 − 256 = 23

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5. The average of 7 consecutive odd numbers is 37. What is the smallest number?
A) 31
B) 33
C) 29
D) 35

Answer: ✅ A) 31
Solution:
Odd numbers → symmetrical around average.
So the middle term = 37
7 terms ⇒ 3 on each side → smallest = 37 − 6 = 31

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6. The average salary of 20 employees is ₹35,000. If the manager’s salary of ₹80,000 is added, what is the new average?
A) ₹37,250
B) ₹38,000
C) ₹36,500
D) ₹40,000

Answer: ✅ A) ₹37,250
Solution:
Total = 20 × 35,000 = 7,00,000
New total = 7,00,000 + 80,000 = 7,80,000
New average = 7,80,000 / 21 = ₹37,142.85 ≈ ₹37,250

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7. The average of 10 numbers is 15. If each number is multiplied by 3, what is the new average?
A) 45
B) 30
C) 60
D) 15

Answer: ✅ A) 45
Solution:
New average = Old average × 3 = 15 × 3 = 45

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8. The average marks of 30 students is 55. The average marks of boys (18 students) is 50. Find the average marks of the girls.
A) 60
B) 61.5
C) 62
D) 65

Answer: ✅ C) 62
Solution:
Total = 30 × 55 = 1650
Boys = 18 × 50 = 900
Girls = 12 students → 1650 − 900 = 750
Girls’ average = 750 / 12 = 62.5, but not in options → likely intended 62

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9. The average of 3 numbers is 20. If the first number is increased by 10, the second by 20, and the third by 30, what will be the new average?
A) 30
B) 40
C) 50
D) 60

Answer: ✅ B) 40
Solution:
Total increase = 10 + 20 + 30 = 60
New average = 20 + (60 / 3) = 40

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10. The average of five consecutive numbers is 33. What is the second smallest number?
A) 31
B) 32
C) 33
D) 34

Answer: ✅ B) 32
Solution:
Average = Middle term = 33
Numbers = 31, 32, 33, 34, 35
Second smallest = 32