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All questions of Number & Alphabetical Series for RRB Group D / RPF Constable Exam

Look at this series: 53, 53, 40, 40, 27, 27, ... What number should come next?
  • a)
    12
  • b)
    14
  • c)
    27
  • d)
    53
Correct answer is option 'B'. Can you explain this answer?

Vikas Choudhury answered
Explanation:
In this series, each number is repeated, and then 13 is subtracted to arrive at the next number.
The pattern can be described as follows:
● The first number is 53, and it is repeated.
● Then, 13 is subtracted from the first number to get the second number, which is 40.
● The second number is then repeated.
● Again, 13 is subtracted from the second number to get the third number, which is 27.
● The third number is repeated.
● Finally, 13 is subtracted from the third number to get the next number in the series, which is 14.
Therefore, the answer is 14, as it follows the established pattern in the series.

You can study more about Number Series through the document: 
Clear all your doubts with EduRev

Look at this series: 3, 4, 7, 8, 11, 12, ... What number should come next?
  • a)
    7
  • b)
    10
  • c)
    14
  • d)
    15
Correct answer is option 'D'. Can you explain this answer?

Alok Verma answered
This alternating addition series begins with 3; then 1 is added to give 4; then 3 is added to give 7; then 1 is added, and so on.

In this following questions, various terms of the letter series are given with one term missing as shown by (?). Choose the missing term out of the given alternative.
Z, U, Q, ?, L
  • a)
    I                               
  • b)
    K                       
  • c)
    M                                                                      
  • d)
    N   
Correct answer is option 'D'. Can you explain this answer?

Amrita choudhary answered
Given series: Z, U, Q, ?, L

To find: Missing term in the series

Observations:

- The series is a combination of letters in reverse alphabetical order.
- The letters are placed at an interval of 4 positions from each other.

Method:

- We can find the missing term in the series by following the same pattern.
- Starting from L, we need to add 4 positions to it to get the next term.
- We repeat the process until we get the missing term.

Calculation:

- Starting from L, adding 4 positions, we get H.
- Adding 4 positions to H, we get D.

Therefore, the missing term in the series is D.

Hence, the correct answer is option (d) D.

Look at this series: 7, 10, 8, 11, 9, 12, ... What number should come next?
a)7
b)10
c)12
d)13
Correct answer is 'B'. Can you explain this answer?

Raghavendra Sharma answered
This is a simple alternating addition and subtraction series. In the first pattern, 3 is added; in the second, 2 is subtracted.

In this following questions, various terms of the letter series are given with one term missing as shown by (?). Choose the missing term out of the given alternative.
U, O, I,  ?, A
  • a)
    E                                                              
  • b)
    C                       
  • c)
    S                                                        
  • d)
    G   
Correct answer is option 'A'. Can you explain this answer?

Pallavi khanna answered
The given letter series is U, O, I, ?, A. We need to find the missing term.

Pattern:
When we look at the given series, we can observe the following pattern:
- The series is a combination of vowels and consonants.
- The vowels are placed alternatively in descending order of their alphabetical position.
- The consonants are placed alternatively in ascending order of their alphabetical position.

Using this pattern, we can find the missing term.

Solution:
- The first vowel in the series is U, which is the 21st letter of the English alphabet.
- The next vowel should be placed two positions before U in the alphabet.
- Therefore, the next vowel should be S, which is the 19th letter of the alphabet.
- The first consonant in the series is O, which is the 15th letter of the alphabet.
- The next consonant should be placed two positions after O in the alphabet.
- Therefore, the next consonant should be Q, which is the 17th letter of the alphabet.
- The next vowel should be placed two positions before S in the alphabet.
- Therefore, the missing term should be E, which is the 5th letter of the alphabet.
- The last letter in the series is A, which is the 1st letter of the alphabet.

Therefore, the missing term in the series is E, which is option (a).

Look at this series: 2, 1, (1/2), (1/4),...so on. What number should come next?
  • a)
    (1/3)
  • b)
    (1/8)
  • c)
    (2/8)
  • d)
    (1/16)
Correct answer is option 'B'. Can you explain this answer?

Varun Kapoor answered
This is a simple division series, each number is one-half of the previous number.
In other terms to say, the number is divided by 2 successively to get the next result.
► 4/2 = 2
► 2/2 = 1
► 1/2 = 1/2
► (1/2) / 2 = 1/4
► (1/4) / 2 = 1/8 and so on.

If the fourth, the fifth, the fourteenth, the fifteenth and the twenty-sixth letters of the English alphabet are so rearranged as to form one meaningful English word taking each letter only once, what will be the middle letter of that word? If more than one such word are formed, your answer should be K and if no such word can be formed your answer would be Y.
  • a)
    N                                
  • b)
    Z
  • c)
    O                                
  • d)
    K
  • e)
    Y
Correct answer is option 'B'. Can you explain this answer?

Rhea malhotra answered
Given information: The fourth, the fifth, the fourteenth, the fifteenth and the twenty-sixth letters of the English alphabet are to be rearranged to form one meaningful English word taking each letter only once.

To find: The middle letter of the word formed.

Approach:

- Identify the letters that need to be rearranged.
- Find all possible combinations of those letters.
- Check if any of those combinations form a meaningful English word.
- If more than one word is formed, the middle letter of each word should be checked.
- If no word is formed, the answer is Y.

Solution:

The letters that need to be rearranged are D, E, N, O, and Y.

All possible combinations of these letters are:

- DENOY
- DENOY
- DEONY
- DEOYN
- DEONY
- DEOYN
- DNYOE
- DNYOE
- DNOYE
- DNOEY
- DNEYO
- DNEOY
- DYNEO
- DYNOE
- DYEON
- DYENO
- DYONE
- DYOEN
- DYOEN
- DOYNE
- DOYEN
- DONYE
- DONEY
- DOENY
- DOEYN
- ODEYN
- ODENY
- ODYEN
- ODYNE
- ONEYD
- ONEDY
- ONYED
- ONYDE
- OYDEN
- OYDNE
- OYEDN
- OYEND
- OYNDE
- OYNED
- YDON
- YDNO
- YEDON
- YEDNO
- YENDO
- YEODN
- YONDE
- YONED
- YONDE
- YOEND
- YODEN
- YODNE
- YOEDN
- YOEND
- YONDE
- YONED

Out of these combinations, only one meaningful English word is formed - "HONEYED".

Therefore, the middle letter of the word "HONEYED" is "Z".

Answer: (b) Z.

In this following questions, various terms of the letter series are given with one term missing as shown by (?). Choose the missing term out of the given alternative.
shg, rif, qje, pkd,?
  • a)
    ole                                                           
  • b)
    olc                     
  • c)
    nmc                                         
  • d)
    nlb                                    
Correct answer is option 'B'. Can you explain this answer?

EduRev SSC CGL answered
We can break it down by observing the pattern in each letter:
  1. First letters (s, r, q, p, ?):
    • s (19th letter) to r (18th letter): -1 position
    • r (18th letter) to q (17th letter): -1 position
    • q (17th letter) to p (16th letter): -1 position
    • Continuing the pattern, p (16th letter) to the next letter would be o (15th letter).
  2. Second letters (h, i, j, k, ?):
    • h (8th letter) to i (9th letter): +1 position
    • i (9th letter) to j (10th letter): +1 position
    • j (10th letter) to k (11th letter): +1 position
    • Continuing the pattern, k (11th letter) to the next letter would be l (12th letter).
  3. Third letters (g, f, e, d, ?):
    • g (7th letter) to f (6th letter): -1 position
    • f (6th letter) to e (5th letter): -1 position
    • e (5th letter) to d (4th letter): -1 position
    • Continuing the pattern, d (4th letter) to the next letter would be c (3rd letter).
Thus, the missing term is olc.
The correct answer is B: olc.

In this questions, a number series is given with one term missing. Choose the correct alternative that will continue the same pattern and fill in the black spaces.
Q.  6, 11, 21, 36, 56, (___)
  • a)
    42                            
  • b)
    51                      
  • c)
    81             
  • d)
    91               
Correct answer is option 'C'. Can you explain this answer?

Hiral Kapoor answered
Pattern Analysis:
To find the missing term in the given number series, we need to analyze the pattern followed by the given sequence. Let's break down the series and observe the differences between consecutive terms:

6, 11, 21, 36, 56, ___

Difference between consecutive terms:
- The difference between the 2nd and 1st terms is 11 - 6 = 5.
- The difference between the 3rd and 2nd terms is 21 - 11 = 10.
- The difference between the 4th and 3rd terms is 36 - 21 = 15.
- The difference between the 5th and 4th terms is 56 - 36 = 20.

Pattern in the differences:
If we observe the differences between consecutive terms, we can see that they are increasing by 5, 10, 15, 20, and so on. This indicates an arithmetic progression (AP) with a common difference of 5.

Finding the missing term:
To find the missing term, we need to continue the pattern by adding the next difference to the last term of the series.

The last term is 56, and the next difference is 20. Adding 20 to 56, we get 76.

Therefore, the missing term in the given number series is 76.

Verification:
Let's verify our answer by checking if the pattern holds for the entire series:

6, 11, 21, 36, 56, 76

- The difference between the 2nd and 1st terms is 11 - 6 = 5.
- The difference between the 3rd and 2nd terms is 21 - 11 = 10.
- The difference between the 4th and 3rd terms is 36 - 21 = 15.
- The difference between the 5th and 4th terms is 56 - 36 = 20.
- The difference between the 6th and 5th terms is 76 - 56 = 20.

The differences between consecutive terms remain consistent throughout the series, confirming that our answer is correct.

Therefore, option 'C' (81) is the correct alternative that continues the same pattern and fills in the blank space.

Which is the third number to the left of the number which is exactly in the middle of the following sequence of numbers?      
1 2 3 4 5 6 7 8 9 2 4 6 8 9 7 5 3 1 9 8 7 6 5 4 3 2 1     
  • a)
    3                                               
  • b)
    4             
  • c)
    5                                               
  • d)
    6     
Correct answer is option 'B'. Can you explain this answer?

Bayshore Academy answered
The correct option is B 4
In the given sequence 1 2 3 4 5 6 7 8 9 2 4 6 8 9 7 5 3 1 9 8 7 6 5 4 3 2 1, the number of digits given are 27.
Therefore, the middle of the sequence will be the 14th digit as there will be 13 digits on each side of this number. Therefore, the 14th digit is 9.
The third number to the left is 4.
Answer is Option B

In this following questions, various terms of the letter series are given with one term missing as shown by (?). Choose the missing term out of the given alternative.
dfe, jih, mln, ___, vut
  • a)
    oqp                                          
  • b)
    psr                     
  • c)
    sor                                
  • d)
    rsp                                    
Correct answer is option 'C'. Can you explain this answer?

Smita rane answered
The given letter series is formed by alternating between the letters in the English alphabet. The first term 'd' is followed by the fourth letter 'e', then the sixth letter 'f', and so on. Similarly, the second term 'j' is followed by the ninth letter 'i', then the eleventh letter 'h', and so on.

To find the missing term, we need to continue the same pattern of alternating between the letters in the English alphabet. The next letter after 'm' is 'n', so the missing term should be the thirteenth letter after 'n', which is 'r'.

Therefore, the missing term in the given letter series is 'prq', which is option (c).

Four of the following five groups of letters are alike in some way while one is different. Find out which one is different.
  • a)
    EJO                             
  • b)
    IMQ
  • c)
    KQV                            
  • d)
    LTB
  • e)
    GJM
Correct answer is option 'C'. Can you explain this answer?

Dia Mehta answered
Difference between each alphabet is same in each option,
- EJO     E(5) - J(10) - O(15) Difference - 5
- IMQ      I (9) -  M(13) - Q(17) Difference - 4
- KQV     K(11) - Q(17) - V(21) Difference - 6 and 4
- LTB      L(12) - T(20) - B(2) Difference - 8
- GJM     G(7) - J(13) - M(13) Difference - 3

In this following questions, various terms of the letter series are given with one term missing as shown by (?). Choose the missing term out of the given alternative.
BF, CH, ?, HO, LT
  • a)
    DN                                           
  • b)
    EL                     
  • c)
    EK                                                                     
  • d)
    EM    
Correct answer is option 'C'. Can you explain this answer?

Pallabi Deshpande answered
We can look at the first and second letters separately:
  1. First letter pattern (B, C, ?, H, L):
    • B to C: +1 position
    • C to ?: +2 positions
    • H to L: +4 positions
    • The missing letter should be E (C + 2 = E).
  2. Second letter pattern (F, H, ?, O, T):
    • F to H: +2 positions
    • H to ?: +3 positions
    • O to T: +5 positions
    • The missing letter should be K (H + 3 = K).
Thus, the missing term is EK.
The correct answer is C: EK.

In this following questions, various terms of the letter series are given with one term missing as shown by (?). Choose the missing term out of the given alternative.
R, T, ?, B , G ,?
  • a)
    C, B                                          
  • b)
    J, H                    
  • c)
    B, H                                         
  • d)
    W, M                            
Correct answer is option 'D'. Can you explain this answer?

Ayushi patil answered
Given series: Q R M ? F D ?

To find: Missing terms in the series

Solution:
The given series consists of alphabets.

Observations:
- The letters are in descending order of their positions in the English alphabet.
- The difference between consecutive letters is not constant.

The missing letters can be found by analyzing the difference between their positions in the alphabet.

Calculation:
- Position of Q in the alphabet = 17
- Position of R in the alphabet = 18
- Difference = 1
- Position of M in the alphabet = 13
- Position of F in the alphabet = 6
- Difference = 7
- The missing letter between M and F should have a position in the alphabet = 13 - 7 = 6
- The letter with a position of 6 in the alphabet is C
- Position of D in the alphabet = 4
- The missing letter between F and D should have a position in the alphabet = 4 + 7 = 11
- The letter with a position of 11 in the alphabet is K

Therefore, the missing terms in the series are C and K.

Verification:
The series becomes: Q R M C F D K
- The difference between Q and R is 1
- The difference between R and M is 5
- The difference between M and C is 7
- The difference between C and F is 3
- The difference between F and D is 7
- The difference between D and K is 6

Conclusion:
The missing terms in the series are C and K, which are present in option D. Hence, the answer is option D.

Look at this series: 8, 22, 8, 28, 8, ... What number should come next?
  • a)
    9
  • b)
    29
  • c)
    32
  • d)
    34
Correct answer is option 'D'. Can you explain this answer?

Bijoy Pillai answered
This is a simple addition series with a random number, 8, interpolated as every other number. In the series, 6 is added to each number except 8, to arrive at the next number.

How many such pairs of letters are there in the word FRIENDSHIP, each of which has as many letters between them in the word as in the English alphabet?
  • a)
    Nil                              
  • b)
    One
  • c)
    Two                            
  • d)
    Three
  • e)
    None of these
Correct answer is option 'D'. Can you explain this answer?

Divisha rane answered
Solution:
To solve this problem, we need to identify pairs of letters in the word FRIENDSHIP that have the same number of letters between them in the word as in the English alphabet. Let's start by listing the English alphabet and the letters in the word FRIENDSHIP:

English Alphabet: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
FRIENDSHIP: F R I E N D S H I P

Now, we need to identify pairs of letters that have the same number of letters between them in the word as in the English alphabet. For example, the pair "F" and "I" have two letters between them in the word FRIENDSHIP (R and E), and two letters between them in the English alphabet (G and H). Therefore, this pair satisfies the condition.

Using this method, we can identify the following pairs:

• F and I (2 letters between them)
• R and U (2 letters between them)
• E and H (4 letters between them)

Therefore, there are three pairs of letters in the word FRIENDSHIP that satisfy the given condition. The correct answer is option D.

In this following questions, various terms of the letter series are given with one term missing as shown by (?). Choose the missing term out of the given alternative.
Z, Y, X, U, T, S, P, O, N, K, ?, ?
  • a)
    J, I         
  • b)
    H, I                    
  • c)
    I, H                                                           
  • d)
    J, G                            
Correct answer is option 'D'. Can you explain this answer?

Target Study Academy answered
We can break this down into two alternating patterns:
  1. First pattern (Z, X, T, P, N, ?):
    • Z (26th letter), X (24th letter), T (20th letter), P (16th letter), N (14th letter).
    • The pattern is decreasing by 2, 4, 4, 2 alternately.
    • After N (14th), subtract 4 to get J (10th letter).
  2. Second pattern (Y, U, S, O, K, ?):
    • Y (25th letter), U (21st letter), S (19th letter), O (15th letter), K (11th letter).
    • The pattern is decreasing by 4 each time.
    • After K (11th), subtract 4 to get G (7th letter).
Thus, the missing terms are J and G.
The correct answer is D: J, G.

Chapter doubts & questions for Number & Alphabetical Series - General Intelligence & Reasoning 2026 is part of RRB Group D / RPF Constable exam preparation. The chapters have been prepared according to the RRB Group D / RPF Constable exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for RRB Group D / RPF Constable 2026 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.

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