Average MCQs

Maths

Average MCQs

Practice Average MCQs with answers and detailed explanations. Learn basic average concepts, average age, marks, salary, speed, combined average, weighted average and advanced aptitude questions designed for SSC, Railway, Banking, UPSC, JKSSB, Police, Teaching and other competitive exams.

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Page 1 of 49
Question #1
The average of 5 numbers is 28. If one number is excluded, the average becomes 25. What is the excluded number?
A. 45
B. 30
C. 35
D. 40
Discuss
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Correct Answer: Option D

Explanation:
Sum of 5 numbers = 5 × 28 = 140. Sum of remaining 4 numbers = 4 × 25 = 100. Excluded number = 140 - 100 = 40.
This question belongs to: Maths Average
Question #2
Find the average of first 10 natural numbers.
A. 5
B. 6.5
C. 5.5
D. 6
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Correct Answer: Option C

Explanation:
Sum of first 10 natural numbers = 10×11/2 = 55. Average = 55/10 = 5.5.
This question belongs to: Maths Average
Question #3
The average age of 6 students is 12 years. If the teacher's age is included, the average becomes 15 years. What is the teacher's age?
A. 33
B. 27
C. 36
D. 30
Discuss
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Correct Answer: Option A

Explanation:
Sum of 6 students' ages = 6×12=72. Sum of 7 persons = 7×15=105. Teacher's age = 105-72=33.
This question belongs to: Maths Average
Question #4
What is the average of the squares of first 5 natural numbers?
A. 9
B. 10
C. 12
D. 11
Discuss
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Correct Answer: Option D

Explanation:
Squares: 1,4,9,16,25 sum=55, average=55/5=11.
This question belongs to: Maths Average
Question #5
The average of 7 consecutive odd numbers is 15. What is the largest number?
A. 23
B. 17
C. 19
D. 21
Discuss
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Correct Answer: Option D

Explanation:
In consecutive odd numbers, average = middle term. So 4th number =15, largest =15+6=21.
This question belongs to: Maths Average
Question #6
The average of 4 numbers is 25. If each number is multiplied by 3, what is the new average?
A. 25
B. 100
C. 50
D. 75
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Correct Answer: Option D

Explanation:
If each number is multiplied by a constant, the average also gets multiplied by that constant. New average = 25×3=75.
This question belongs to: Maths Average
Question #7
The average weight of 10 students is 45 kg. If a new student joins, the average becomes 46 kg. What is the weight of the new student?
A. 54 kg
B. 55 kg
C. 56 kg
D. 57 kg
Discuss
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Correct Answer: Option C

Explanation:
Total weight of 10 = 450. Total of 11 = 11×46=506. New student's weight = 506-450=56.
This question belongs to: Maths Average
Question #8
Find the average of all even numbers between 1 and 20 (inclusive of 20).
A. 10
B. 11
C. 10.5
D. 12
Discuss
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Correct Answer: Option B

Explanation:
Even numbers: 2,4,...,20. Sum = 2+4+...+20 = 2×(1+2+...+10)=2×55=110. Count=10. Average=110/10=11.
This question belongs to: Maths Average
Question #9
The average of 5 numbers is 40. If each number is decreased by 5, what is the new average?
A. 45
B. 35
C. 30
D. 40
Discuss
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Correct Answer: Option B

Explanation:
If each number is decreased by a constant, the average also decreases by that constant. New average =40-5=35.
This question belongs to: Maths Average
Question #10
The average of 3 numbers is 18. If two of the numbers are 15 and 20, find the third number.
A. 20
B. 18
C. 19
D. 17
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Correct Answer: Option C

Explanation:
Sum of 3 numbers = 3×18=54. Sum of two =15+20=35. Third =54-35=19.
This question belongs to: Maths Average
Question #11
The average of a set of 8 numbers is 32. If one number is 50, what is the average of the remaining numbers?
A. 31.00
B. 28.57
C. 30.25
D. 29.43
Discuss
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Correct Answer: Option D

Explanation:
Sum of 8 = 256. Sum of remaining 7 = 256-50=206. Average = 206/7 ≈ 29.43.
This question belongs to: Maths Average
Question #12
What is the average of the first 5 multiples of 3?
A. 9
B. 10
C. 12
D. 8
Discuss
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Correct Answer: Option A

Explanation:
Multiples: 3,6,9,12,15 sum=45, average=45/5=9.
This question belongs to: Maths Average
Question #13
The average of 11 numbers is 55. What is the sum of the numbers?
A. 605
B. 615
C. 600
D. 550
Discuss
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Correct Answer: Option A

Explanation:
Sum = Average × Number =55×11=605.
This question belongs to: Maths Average
Question #14
The average of 15 observations is 20. If each observation is increased by 3, what is the new average?
A. 20
B. 30
C. 23
D. 17
Discuss
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Correct Answer: Option C

Explanation:
New average = old average + increase =20+3=23.
This question belongs to: Maths Average
Question #15
The average age of a family of 5 members is 30 years. The youngest member is 5 years old. What is the average age of the remaining 4 members?
A. 36.25
B. 37.5
C. 35
D. 34
Discuss
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Correct Answer: Option A

Explanation:
Sum of ages = 5×30=150. Sum of remaining 4 =150-5=145. Average =145/4=36.25.
This question belongs to: Maths Average
Question #16
The average of 6 numbers is 22. If one number is 10, find the average of the remaining 5 numbers.
A. 24.4
B. 25
C. 22.8
D. 23.6
Discuss
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Correct Answer: Option A

Explanation:
Sum of 6 = 6×22=132. Sum of 5 =132-10=122. Average =122/5=24.4.
This question belongs to: Maths Average
Question #17
What is the average of the first 7 multiples of 5?
A. 30
B. 25
C. 15
D. 20
Discuss
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Correct Answer: Option D

Explanation:
Multiples: 5,10,15,20,25,30,35 sum=140, count=7, avg=20.
This question belongs to: Maths Average
Question #18
The average of 4 numbers is 30. If the numbers are in the ratio 1:2:3:4, find the largest number.
A. 24
B. 36
C. 48
D. 60
Discuss
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Correct Answer: Option C

Explanation:
Sum = 4×30=120. Ratio sum =1+2+3+4=10. Largest = (4/10)×120=48.
This question belongs to: Maths Average
Question #19
The average of 5 consecutive even numbers is 12. What is the smallest number?
A. 10
B. 6
C. 8
D. 12
Discuss
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Correct Answer: Option C

Explanation:
In consecutive even numbers, average = middle number. So middle (3rd) =12. Smallest =12-4=8.
This question belongs to: Maths Average
Question #20
The average marks of 25 students is 70. If the marks of one student were misread as 80 instead of 60, find the correct average.
A. 69.2
B. 68.8
C. 70.0
D. 69.8
Discuss
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Correct Answer: Option A

Explanation:
Total sum misread =25×70=1750. Correct sum =1750 -80 +60 =1730. Correct average =1730/25=69.2.
This question belongs to: Maths Average

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