Back to Practice Quantitative Aptitude

Averages - Practice MCQs for CCAT

60 Questions Section A: Fundamentals Quantitative Aptitude

Averages Question Bank for C-CAT

Topic-wise Averages MCQs for CDAC C-CAT preparation with answers and explanations.

Q1.
The average of 5 numbers is 20. If one number is excluded, the average becomes 18. Find the excluded number.
A24
B28
C26
D30
Show Answer & Explanation

Correct Answer: B - 28

Sum = 5×20 = 100. New sum = 4×18 = 72. Excluded = 100-72 = 28.

Q2.
The average age of 30 students is 15 years. If the teacher's age is included, the average increases by 1. What is the teacher's age?
A40 years
B46 years
C44 years
D50 years
Show Answer & Explanation

Correct Answer: B - 46 years

Sum of students = 450. New sum = 31×16 = 496. Teacher = 496-450 = 46.

Q3.
The average of first 5 multiples of 3 is:
A8
B9
C10
D11
Show Answer & Explanation

Correct Answer: B - 9

Multiples: 3,6,9,12,15. Sum = 45. Average = 45/5 = 9.

Q4.
The average of 11 numbers is 50. The average of first 6 is 48 and last 6 is 52. Find the 6th number.
A48
B54
C52
D50
Show Answer & Explanation

Correct Answer: D - 50

Sum of 11 = 550. First 6 = 288, Last 6 = 312. 6th = 288+312-550 = 50.

Q5.
The average weight of 8 persons increases by 2.5 kg when a new person comes in place of one weighing 65 kg. Weight of new person?
A75 kg
B80 kg
C85 kg
D90 kg
Show Answer & Explanation

Correct Answer: C - 85 kg

Increase in sum = 8×2.5 = 20. New person = 65+20 = 85 kg.

Q6.
The average of 6 numbers is 30. If one number is removed, the average becomes 28. Find the removed number.
A38
B44
C42
D40
Show Answer & Explanation

Correct Answer: D - 40

Sum = 180. New sum = 5×28 = 140. Removed = 180-140 = 40.

Q7.
A batsman has an average of 40 runs in 10 innings. How many runs must he score in the next innings to increase his average by 2?
A52
B62
C58
D68
Show Answer & Explanation

Correct Answer: B - 62

New average = 42 for 11 innings. Total = 462. Previous = 400. Needed = 62.

Q8.
The average of 5 consecutive odd numbers is 21. The largest number is:
A23
B29
C27
D25
Show Answer & Explanation

Correct Answer: D - 25

For consecutive odds, average = middle number = 21. Numbers: 17,19,21,23,25.

Q9.
The average marks of three batches of 55, 60, and 45 students respectively is 50, 55, and 60. Find overall average.
A54.5
B54.68
C55
D55.25
Show Answer & Explanation

Correct Answer: B - 54.68

Total marks = 2750+3300+2700 = 8750. Total students = 160. Avg = 54.68.

Q10.
The average of A and B is 45. The average of B and C is 50. The average of C and A is 55. Find A.
A40
B45
C50
D55
Show Answer & Explanation

Correct Answer: C - 50

A+B=90, B+C=100, C+A=110. Adding: 2(A+B+C)=300, so A+B+C=150. A=150-100=50.

Q11.
The average of 10 numbers is 23. If each number is increased by 4, the new average is:
A23
B27
C25
D29
Show Answer & Explanation

Correct Answer: B - 27

When each number increases by 4, average also increases by 4. New average = 23+4 = 27.

Q12.
Average of 20 observations is 45. It was later found that one observation 78 was wrongly noted as 48. Correct average is:
A48
B47
C47.5
D46.5
Show Answer & Explanation

Correct Answer: D - 46.5

Increase = 78-48 = 30. New sum increases by 30. New average = 45 + 30/20 = 46.5.

Q13.
The average of first 7 multiples of 7 is:
A21
B28
C35
D42
Show Answer & Explanation

Correct Answer: B - 28

Multiples: 7,14,21,28,35,42,49. Average = 196/7 = 28. Or average = (first+last)/2 = (7+49)/2 = 28.

Q14.
In a cricket match, average of 5 batsmen is 36. If the 6th batsman scores 55, new average is:
A38.5
B40
C39.17
D41.5
Show Answer & Explanation

Correct Answer: C - 39.17

Total = 5×36 + 55 = 235. Average = 235/6 = 39.17.

Q15.
Average age of A, B, C, D five years ago was 45. Average age now after including E is 49. Age of E is:
A60
B50
C55
D45
Show Answer & Explanation

Correct Answer: D - 45

Sum of A,B,C,D now = 4×50 = 200. Sum of 5 now = 5×49 = 245. E = 45.

Q16.
Average salary of 19 workers is ₹5000. Average salary of 12 male workers is ₹4500. Average salary of female workers is:
A₹5500
B₹5714
C₹5857
D₹6000
Show Answer & Explanation

Correct Answer: C - ₹5857

Total = 95000. Males = 54000. Females = 41000. Female avg = 41000/7 = 5857.

Q17.
Average of 10 numbers is 0. At most how many numbers can be greater than 0?
A0
B9
C5
D10
Show Answer & Explanation

Correct Answer: B - 9

At most 9. If 9 are positive, 1 must be negative to make sum 0. All 10 positive is impossible.

Q18.
The average weight of 3 boys A, B, C is 54 kg. When D joins, average becomes 53 kg. If E (weight = D+3) replaces A, average becomes 51 kg. Weight of A is:
A64 kg
B60 kg
C68 kg
D72 kg
Show Answer & Explanation

Correct Answer: B - 60 kg

ABC = 162. ABCD = 212, so D = 50. BCDE = 204. BCD = 50+162-A. BCE + E = 204...

Q19.
A vehicle travels 40 km at 20 km/h, 40 km at 40 km/h, and 40 km at 60 km/h. Average speed is:
A30 km/h
B40 km/h
C35 km/h
D32.7 km/h
Show Answer & Explanation

Correct Answer: D - 32.7 km/h

Time = 2+1+2/3 = 11/3 hrs. Distance = 120 km. Avg = 120×3/11 = 32.7 km/h.

Q20.
Average of 5 numbers is 4.4. Average of 3 of them is 3.2. Average of remaining 2 is:
A6.0
B5.8
C5.5
D6.2
Show Answer & Explanation

Correct Answer: A - 6.0

Sum of 5 = 22. Sum of 3 = 9.6. Sum of 2 = 12.4. Average = 6.2.

Q21.
Average of first 10 natural numbers is:
A5.5
B5
C6
D10
Show Answer & Explanation

Correct Answer: A - 5.5

Sum=55. Average=55/10=5.5.

Q22.
Average of 5 numbers is 20. If one number is removed, average becomes 18. The removed number is:
A30
B24
C28
D22
Show Answer & Explanation

Correct Answer: C - 28

Total=100. New total=72. Removed=100-72=28.

Q23.
A batsman's average after 20 innings is 35. After 21st innings, average rises to 36. Runs in 21st innings:
A50
B55
C57
D56
Show Answer & Explanation

Correct Answer: D - 56

Total after 20=700. Total after 21=756. Runs=56.

Q24.
Average age of 5 students is 14. Average age of 5 students and a teacher is 17. Teacher's age:
A40
B29
C35
D32
Show Answer & Explanation

Correct Answer: D - 32

Total students=70. Total with teacher=102. Teacher=32.

Q25.
Average of 10 numbers is 12. Average of first 6 is 10 and last 5 is 14. The 6th number is:
A12
B10
C8
D14
Show Answer & Explanation

Correct Answer: B - 10

Total=120. First 6 total=60. Last 5 total=70. 6th number=60+70-120=10.

Q26.
The average of 4 consecutive even numbers is 15. Largest number:
A20
B16
C18
D14
Show Answer & Explanation

Correct Answer: C - 18

Numbers: x, x+2, x+4, x+6. Average=(4x+12)/4=x+3=15. x=12. Largest=18.

Q27.
Average weight of a class of 30 is 40 kg. New student joins, average becomes 39.5 kg. New student's weight:
A30 kg
B25 kg
C20 kg
D24.5 kg
Show Answer & Explanation

Correct Answer: D - 24.5 kg

Total=1200. New total=31×39.5=1224.5. New student=24.5 kg.

Q28.
Average marks of 12 students is 36. Average of top 4 is 45 and bottom 4 is 24. Average of remaining 4:
A39
B36
C42
D30
Show Answer & Explanation

Correct Answer: A - 39

Total=432. Top4=180. Bottom4=96. Remaining=432-180-96=156. Avg=156/4=39.

Q29.
The average of first 50 natural numbers is:
A25.5
B25
C26
D50
Show Answer & Explanation

Correct Answer: A - 25.5

Average = (50+1)/2 = 25.5.

Q30.
Average monthly salary of 20 workers is ₹15000. Manager's salary added, average becomes ₹16000. Manager's salary:
A₹40000
B₹31000
C₹25000
D₹36000
Show Answer & Explanation

Correct Answer: D - ₹36000

Workers total=300000. With manager=336000. Manager=36000.

Q31.
Three numbers are in ratio 3:5:7. Their average is 45. Largest number:
A63
B60
C70
D55
Show Answer & Explanation

Correct Answer: A - 63

3x+5x+7x=135. 15x=135. x=9. Largest=63.

Q32.
Average of 8 observations is 25. If two observations 14 and 36 are removed, new average is:
A25
B24
C26
D23
Show Answer & Explanation

Correct Answer: A - 25

Total=200. After removal=200-14-36=150. New avg=150/6=25.

Q33.
A car travels 100 km at 50 km/h and 100 km at 40 km/h. Average speed:
A48 km/h
B45 km/h
C42 km/h
D44.44 km/h
Show Answer & Explanation

Correct Answer: D - 44.44 km/h

Total time = 2+2.5 = 4.5 hours. Avg speed = 200/4.5 = 44.44 km/h.

Q34.
Average of 5 numbers is 8. Each number is multiplied by 3. New average:
A24
B8
C15
D40
Show Answer & Explanation

Correct Answer: A - 24

When each number is multiplied by 3, average also becomes 8×3=24.

Q35.
A student got 60, 70, 80, 90 in four subjects. How much must he get in 5th to average 80?
A95
B100
C90
D85
Show Answer & Explanation

Correct Answer: B - 100

Required total=400. Current=300. Need=100.

Q36.
Average age of husband and wife 5 years ago was 23. Now with child, average age of family is 20. Child's age:
A4 years
B2 years
C5 years
D1 year
Show Answer & Explanation

Correct Answer: A - 4 years

Five years ago the couple's total age was 46. Now their total is 56. The family total now is 3 x 20 = 60, so the child's age is 4 years.

Q37.
Average of 11 results is 50. Average of first 6 is 48 and last 6 is 52. The 6th result is:
A52
B48
C50
D55
Show Answer & Explanation

Correct Answer: C - 50

Total=550. First6=288. Last6=312. 6th=288+312-550=50.

Q38.
Weighted average of 30 boys (avg 70) and 20 girls (avg 80):
A74
B75
C72
D76
Show Answer & Explanation

Correct Answer: A - 74

WA=(30×70+20×80)/50=(2100+1600)/50=3700/50=74.

Q39.
If each of 5 numbers increased by 5, the new average increases by:
A1
B25
C5
D10
Show Answer & Explanation

Correct Answer: C - 5

Adding constant to each number increases average by same constant: 5.

Q40.
The average of squares of first 5 natural numbers:
A15
B10
C11
D9
Show Answer & Explanation

Correct Answer: C - 11

(1+4+9+16+25)/5=55/5=11.

Q41.
Average of x, 2x, 3x, 4x, 5x is:
A3x
B2.5x
C4x
D5x
Show Answer & Explanation

Correct Answer: A - 3x

Sum=15x. Average=15x/5=3x.

Q42.
A class average drops from 65 to 62 when a new student scoring 35 joins. Original class strength:
A8
B10
C9
D12
Show Answer & Explanation

Correct Answer: C - 9

65n+35=62(n+1). 65n+35=62n+62. 3n=27. n=9.

Q43.
Average of 7 consecutive numbers is 33. Largest is:
A36
B35
C37
D38
Show Answer & Explanation

Correct Answer: A - 36

Middle number=33. Numbers: 30,31,32,33,34,35,36. Largest=36.

Q44.
A person travels half distance at 40 km/h and half at 60 km/h. Average speed:
A48 km/h
B50 km/h
C45 km/h
D55 km/h
Show Answer & Explanation

Correct Answer: A - 48 km/h

Average=2×40×60/(40+60)=4800/100=48 km/h.

Q45.
Average of 20 numbers is 0. At most how many can be greater than 0?
A0
B10
C19
D20
Show Answer & Explanation

Correct Answer: C - 19

19 can be positive if the 20th is negative enough to bring average to 0.

Q46.
Mean of 100 items was 50. Later two items 92 and 8 were found wrong, correct values being 192 and 18. Correct mean:
A51.10
B50.50
C51.00
D52.00
Show Answer & Explanation

Correct Answer: A - 51.10

New total=5000-92-8+192+18=5110. New mean=51.10.

Q47.
Average of all prime numbers between 1 and 20:
A10
B9.625
C8.5
D11
Show Answer & Explanation

Correct Answer: B - 9.625

Primes: 2,3,5,7,11,13,17,19. Sum=77. Avg=77/8=9.625.

Q48.
Average salary increases by ₹300 when a person earning ₹9500 is replaced by new person. If there are 20 people, new person's salary:
A₹15500
B₹12000
C₹14000
D₹16000
Show Answer & Explanation

Correct Answer: A - ₹15500

Total increase=20×300=6000. New person=9500+6000=15500.

Q49.
Average age of a group of 10 persons increases by 2 years when 2 women of 20 and 24 are replaced. Average age of new women:
A34 years each
B30 years each
C32 years each
D28 years each
Show Answer & Explanation

Correct Answer: C - 32 years each

Total increase=10×2=20. New women total=20+24+20=64. Average=64/2=32 each.

Q50.
Average of first n odd numbers is:
An+1
Bn
Cn-1
D2n-1
Show Answer & Explanation

Correct Answer: B - n

First n odd numbers: 1,3,5...,(2n-1). Sum=n². Average=n²/n=n.

Q51.
Average of 20 numbers is 36. If one number 52 is removed, new average is:
A34.8
B35.0
C35.2
D35.4
Show Answer & Explanation

Correct Answer: C - 35.2

Total=720. New total=668 for 19 numbers. Average=668/19=35.157, closest 35.2.

Q52.
Average age of 5 people is 28. A new person joins and average becomes 30. New person's age is:
A36
B38
C40
D42
Show Answer & Explanation

Correct Answer: C - 40

Old total=140. New total=180. New age=40.

Q53.
The average of first 50 natural numbers is:
A24.5
B25
C25.5
D26
Show Answer & Explanation

Correct Answer: C - 25.5

Average of first n natural numbers = (n+1)/2 = 25.5.

Q54.
Average of 8 observations is 15. If each observation is multiplied by 3 and then increased by 2, new average is:
A45
B47
C49
D51
Show Answer & Explanation

Correct Answer: B - 47

New average = 3 x 15 + 2 = 47.

Q55.
Average marks of a class of 30 is 62. If boys average 58 and girls average 68, number of girls is:
A10
B12
C14
D16
Show Answer & Explanation

Correct Answer: B - 12

Let girls=g. 68g + 58(30-g)=62x30. 10g=120, so g=12.

Q56.
Average of 7 consecutive odd numbers is 33. Largest number is:
A37
B39
C41
D43
Show Answer & Explanation

Correct Answer: B - 39

For consecutive odd numbers, average is middle term. Numbers are 27 to 39, largest 39.

Q57.
A batsman scores 80 in his 15th innings and average increases by 2. New average is:
A50
B52
C54
D56
Show Answer & Explanation

Correct Answer: B - 52

Let old average after 14 innings be x. (14x+80)/15 = x+2 gives x=50, new average=52.

Q58.
Average of x and y is 24, average of y and z is 30, average of z and x is 36. Value of x+y+z is:
A84
B90
C96
D108
Show Answer & Explanation

Correct Answer: B - 90

x+y=48, y+z=60, z+x=72. Twice sum=180, so sum=90.

Q59.
A group average is 45. If 5 members averaging 60 leave, average of remaining 15 becomes:
A38
B40
C42
D43
Show Answer & Explanation

Correct Answer: B - 40

Original total=20x45=900. Leaving total=300. Remaining total=600 for 15, average=40.

Q60.
Average of 10 numbers is 0. How many numbers must be negative?
AAt least 1
BAt least 5
CCannot be determined
DExactly 5
Show Answer & Explanation

Correct Answer: C - Cannot be determined

The average only fixes the sum as 0. The signs of individual numbers cannot be determined.

Showing 1-10 of 60 questions

More Quantitative Aptitude Topics

Number System Percentages Profit & Loss Ratio & Proportion Time & Work Time & Distance