Odd Man Out and Series Aptitude

Odd Man Out and Series problems test one’s ability to discern patterns and sequences in numbers, letters, or symbols. These problems require identifying the underlying rule in a series or finding which element does not fit a certain pattern. They are common in various competitive exams and are key in assessing logical reasoning and analytical skills.

1. Find the odd one out: 3, 5, 11, 14, 17, 19

a) 3
b) 11
c) 14
d) 17

Answer:

c) 14

Explanation:


All except 14 are prime numbers.

2. Choose the number that does not belong: 64, 125, 216, 312, 729

a) 125
b) 216
c) 312
d) 729

Answer:

c) 312

Explanation:


All except 312 are perfect cubes (4^3, 5^3, 6^3, 9^3). 312 is not a perfect cube.

3. Find the odd one out: 2, 6, 12, 20, 30, 42, 56

a) 12
b) 20
c) 30
d) 42

Answer:

c) 30

Explanation:


All others are products of two consecutive numbers (2×1, 3×2, 4×3, 6×5, 7×6). 30 is not.

4. Select the odd one: ACD, EGJ, IKN, MPR, SVY

a) ACD
b) EGJ
c) MPR
d) SVY

Answer:

c) MPR

Explanation:


In all others, the second and third letters are consecutive in the alphabet.

5. Identify the odd series: 1, 4, 9, 16, 25, 36; 2, 3, 5, 8, 12, 17; 3, 5, 8, 12, 17, 23; 4, 7, 11, 16, 22, 29

a) 1, 4, 9, 16, 25, 36
b) 2, 3, 5, 8, 12, 17
c) 3, 5, 8, 12, 17, 23
d) 4, 7, 11, 16, 22, 29

Answer:

a) 1, 4, 9, 16, 25, 36

Explanation:


All in option a) are perfect squares. The others are not.

6. Choose the odd one out: 41, 43, 47, 53, 61

a) 41
b) 43
c) 53
d) 61

Answer:

d) 61

Explanation:


All except 61 are prime numbers less than 50.

7. Identify the odd series: ABC, DEF, GHI, JKL, MNO, QRS

a) ABC
b) DEF
c) JKL
d) QRS

Answer:

d) QRS

Explanation:


All others are sequences of three consecutive alphabets. QRS skips P.

8. Find the odd one out: 121, 144, 169, 196, 225, 256, 289

a) 144
b) 169
c) 196
d) 256

Answer:

d) 256

Explanation:


All except 256 are odd perfect squares. 256 is an even perfect square (16^2).

9. Choose the odd one: 8, 27, 64, 100, 125

a) 27
b) 64
c) 100
d) 125

Answer:

c) 100

Explanation:


All except 100 are perfect cubes.

10. Identify the odd series: 6-18, 10-30, 14-42, 18-54, 22-66

a) 6-18
b) 10-30
c) 14-42
d) 22-66

Answer:

d) 22-66

Explanation:


In all others, the second number is three times the first. In 22-66, it is not.

11. Find the odd one out: 7, 14, 28, 35, 49

a) 7
b) 14
c) 28
d) 35

Answer:

d) 35

Explanation:


All except 35 are multiples of 7 and less than 30.

12. Select the odd one: 3, 8, 15, 24, 35, 48

a) 8
b) 15
c) 24
d) 35

Answer:

d) 35

Explanation:


All others are one less than a perfect square.

13. Identify the odd series: 579, 264, 863, 642, 461

a) 579
b) 264
c) 863
d) 642

Answer:

c) 863

Explanation:


In all others, the middle digit is the sum of the other two.

14. Choose the odd one out: 1/3, 2/5, 3/7, 4/9, 5/11

a) 1/3
b) 2/5
c) 3/7
d) 4/9

Answer:

d) 4/9

Explanation:


All others are fractions where the denominator is two more than the numerator.

15. Find the odd one out: 0, 5, 10, 15, 20, 25, 30

a) 0
b) 10
c) 20
d) 25

Answer:

d) 25

Explanation:


All except 25 are multiples of 5 and less than or equal to 30.

16. Select the odd one: AEG, BFI, CHK, DJL, EKN

a) AEG
b) BFI
c) CHK
d) EKN

Answer:

d) EKN

Explanation:


In all others, the second and third letters are consecutive in the alphabet.

17. Identify the odd series: 1-3, 4-12, 6-18, 8-24, 10-30

a) 1-3
b) 4-12
c) 6-18
d) 10-30

Answer:

b) 4-12

Explanation:


In all others, the second number is three times the first. In 4-12, it is not.

18. Choose the odd one out: 31, 37, 41, 43, 53

a) 31
b) 37
c) 41
d) 53

Answer:

a) 31

Explanation:


All except 31 are prime numbers greater than 30.

19. Find the odd one out: 6, 12, 18, 24, 30, 36, 45

a) 12
b) 18
c) 30
d) 45

Answer:

d) 45

Explanation:


All others are multiples of 6.

20. Select the odd one: 121, 131, 141, 151, 161

a) 121
b) 131
c) 141
d) 161

Answer:

c) 141

Explanation:


All others are prime numbers.

21. Identify the odd series: 1357, 2468, 3579, 4680, 5791

a) 1357
b) 2468
c) 3579
d) 4680

Answer:

d) 4680

Explanation:


In all others, each digit is one more than the previous digit.

22. Choose the odd one out: 16, 25, 36, 49, 64

a) 16
b) 25
c) 36
d) 49

Answer:

a) 16

Explanation:


All except 16 are odd perfect squares.

23. Find the odd one out: 2-10, 3-15, 4-20, 5-25, 6-30

a) 2-10
b) 3-15
c) 4-20
d) 5-25

Answer:

d) 5-25

Explanation:


In all others, the second number is five times the first.

24. Select the odd one: CAT, BAT, RAT, MAT, PAT

a) CAT
b) BAT
c) RAT
d) MAT

Answer:

d) MAT

Explanation:


All others have animals' names.

25. Select the odd one: CAT, BAT, RAT, MAT, PAT

a) CAT
b) BAT
c) RAT
d) MAT

Answer:

d) MAT

Explanation:


All others represent names of animals, whereas MAT does not.

26. Identify the odd series: 1-4-9, 2-8-18, 3-12-27, 4-16-36, 5-20-45

a) 1-4-9
b) 2-8-18
c) 4-16-36
d) 5-20-45

Answer:

b) 2-8-18

Explanation:


In all series except 2-8-18, the third number is the square of the first number (1^2 = 1, 3^2 = 9, 4^2 = 16, 5^2 = 25). In 2-8-18, 18 is not the square of 2.

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