Number Series Reasoning Questions with Answers

3 2 2 5 5 5 7 8 8 9 11 11 ?

1. 12

2. 11

3. 9

4. 14

5. 16

Sol: Option 2
Explanation: There are three parallel series going on in this question. The 1^st, 4^th, 7^th terms are using logic of -1, 2^nd, 5^th and 8^th terms are using logic of +1 and 3^rd, 6^th and 9^th terms are using logic of +1 again. Answer will be 11, which belongs to 1^st, 4^th and 7^th term.
7 9 8 6 10 9 5 11 10 ? 12

1. 4

2. 11

3. 56

4. 5

5. 29

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Sol: Option 1
Explanation:There are three parallel series going on in this question. The 1^st, 4^th, 7^th terms are using logic of -1, 2^nd, 5^th and 8^th terms are using logic of +1 and 3^rd, 6^th and 9^th terms are using logic of +1 again. Answer will be 4, which belongs to 1^st, 4^th and 7^th term.
1 3 2 6 3 11 4 18 5 ?

1. 27

2. 25

3. 23

4. 29

5. 20

Sol: Option 1
Explanation:
13 17 23 29 31 37 ??

1. 22

2. 41

3. 19

4. 23

5. 27

Sol: Option 2
Explanation: The given series is a prime number series. Hence the next prime number in this sequence would be 41.
17 16 14 12 11 8 8 ?

1. 4

2. 7

3. 3

4. 2

5. None of the above

Sol: Option 1
Explanation: There are two series:
I^st : 17 14 11 8 and 2^nd: 16 12 8 ?
In first series, -3 , -3 ,-3….. and in 2^nd series , -4 , -4 ,-4….
Therefore, next term will be 8 – 4 = 4.

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Practice Questions Level 01

Directions for questions 6-10: In each of the following number series only one number is wrong. Find out the wrong number.

3, 12, 8, 19, 13, 32, 18, 42, 23, 52

1. 12

2. 19

3. 42

4. 32

5. None of the above

Sol: Option 2
Explanation: The sequence is a combination of following two series:
I. 3, 8, 13, 18, 23 and II. 12, 19, 32, 42, 52
The pattern in I has a constant difference of +5, and the pattern in II has a constant difference of +10. So, in II, 19 is wrong and should be replaced by (12+10) i.e. 22
31, 2, 41, 3, 52, 4, 61, 5, 71, 6

1. 41

2. 61

3. 52

4. 31

5. 6

Sol: Option 3
Explanation: The sequence is a combination of two given series:
I. 31, 41, 52, 61, 71 and II. 2, 3, 4, 5, 6
So, the pattern in I is + 10
Thus, 52 is wrong and should be replaced by (41 + 10) i.e. 51.
10, 5, 19, 12, 39, 26, 73, 54

1. 5

2. 19

3. 39

4. 26

5. 54

Sol: Option 3
Explanation: The sequence is a combination of the following two series:
I. 10, 19, 39, 73, and II. 5, 12, 26, 54
The pattern in I becomes + 9, + 18, + 36, So 39 should be replaced by 37. So, 39 is wrong.
1, 10, 9, 16, 25, 26, 49

1. 1

2. 16

3. 26

4. 9

5. 49

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Sol: Option 2
Explanation: The given sequence is a combination of two series:
I. 1, 9, 25, 49 and II. 10, 16, 26
The pattern in I is +8, +16, +24.
The sequence in II is 3² + 1, 4² + 1, 5² + 1
So, 16 is wrong and must be replaced by (4² + 1) i.e. 17.
1, 125, 729, 2177

1. 2177

2. 729

3. 125

4. 1

5. 121

Sol: Option 1
Explanation: 1, 125, 729, 2177
1 = 1³ , 125 = 5³, 729 = 9³. So, next number would be 13³= 2197
Therefore, 2177 is wrong.