# Letter Series/Alphabet Series Questions

Letter series/ Alphabet series questions are part of the general intelligence and reasoning section. Letter series questions are the most common and important questions for competitive exams such as GRE, GMAT, etc. These are easy questions that every student should attempt in these exams. The best way to master these letter cluster series questions is to practice them as many as possible.

In this section, we will learn different types of letter series problems and we will share some tricks and shortcuts to solve these alphabet series problems.

## What are letter series or alphabet series questions?

Letter series questions are consist of a series of letters in which the letters are arranged in a particular order. We have to identify the letter series pattern and find out the missing letter in the series.

Examples:

1. A, D, G, J, M, _
2. AB, DE, GH,_ _, JK, MN
3. ABC, PQR, STU, V_ _

## Types of letter series questions and how to solve them (With example)

### Type I – Single Alphabet/Letter Series

These letter series questions are consists of series of single letter/alphabet arranged in a particular pattern.

Solved Question
• Select the letter that can replace the question mark (?) in the following series.
• U, O, I, ? , A
• a) E
• b) C
• c) S
• d) G

a) E

Show Solution

The series is consists of vowels written in reverse order.

Vowels: A E I O U

The vowel in reverse order: U O I E A

Hence, our answer is option a) E

#### Tip: Convert Alphabet series into number series

Let’s call these numbers as alphabet numbers.

For Example:

The alphabet number of O is 15

The alphabet number of V is 22

Solved Question
• Select the letters that can replace the question marks (?) in the following series.
• Y, W, U, S, Q, ?, ?
• a) N, J
• b) M, L
• c) J, R
• d) L, M
• e) O, M

e) O, M

Show Solution

Best way to solve these type of questions is by converting the alphabets series into number as follows

After mapping the alphabet series into numerical series, we can easily see that this is a decreasing series with a common difference of 2.

So the next two alphabets will be those who have numerical value as 15 and 13

• 25, 23, 21, 19, 17, 15, 13

Now, again convert number series to alphabet series

• 15 becomes ‘O’
• 13 becomes ‘M’

Hence Option e) O, M is correct.

#### Circular Arrangement Series

Do not try to remember this table.

In case of circular arrangement series, add 26 with the alphabet number

For example:

Number for letter ‘M’ in circular series will be 26+13 = 39

Number for letter ‘E’ in circular series will be 26+5 = 31

Solved Question
• Find the missing letter in the given series:
• V, A, H, __
• a) M
• b) N
• c) O
• d) P
• e) Q

e) Q

Show Solution

Let’s first convert alphabet series into number series

V, A, H, ? becomes 22, 27, 34, ?

Now we can observe that the difference between

first and second number is 5,

second and third number is 7,

So the difference between third and fourth should be 9.

To get the missing number in the series,

add 9 to third number i.e, 34+9 = 43

so the series now becomes 22, 27, 34, 43

Now convert this number series into alphabet series

43 becomes Q

Our alphabet series becomes V, A, H, Q

Hence, Option e) Q is correct.

#### Practice Problems

Question 1
1. Select the letters that can replace the question marks (?) in the following series.
2. A, B, D, G, ?
3. a) M
4. b) L
5. c) K
6. d) H

1. c) K

Question 2
1. Select the letters that can replace the question marks (?) in the following series.
2. A, C, F, H, ?, M
3. a) L
4. b) K
5. c) J
6. d) I

1. b) K

Question 3
1. Find the missing letter in the following series
2. Z, S, W, O, T, K, Q, G, ?, ?
3. a) N, C
4. b) N, D
5. c) O, C
6. d) O, D

1. a) N, C

Question 4
1. Select the letters that can replace the question marks (?) in the following series
2. Z, L, X, J, V, H, T, F, ?, ?
3. a) R, D
4. b) R, E
5. c) S, E
6. d) Q, D

1. a) R, D

Question 5
1. Find the missing letters in the given series
2. b e d f ? h j ? l
3. a) i, m
4. b) m, i
5. c) i, n
6. d) j, m

1. a) i, m

### Type II – Series with two alphabets

These letter series questions are consists of series of two letter/alphabet arranged in a particular pattern.

Solved Question
• Select the letters that can replace the question marks (?) in the following series
• AZ, BY, CX, ?
• a) EF
• b) GH
• c) IJ
• d) DE
• e) DW

e) DW

Show Solution

First convert alphabet series into number series

AZ, BY, CX, ? becomes 1-26, 2-25, 3-24, ?-?

After converting to number series, split this series into two series as follows

Series I – 1, 2 , 3, ?

Series II – 26, 25, 24, ?

Now these solve these two series separately

Series I – this is a progression series with common difference of 1, so the missing number becomes 3+1 = 4

1, 2, 3, 4

Series II- This is a decreasing series with common difference of 1, so the missing number becomes 24-1 = 23

26, 25, 24, 23

Now, merge these two series again, so the combined series becomes

1-26, 2-25, 3-24, 423

Now convert this number series into alphabet series

4-23 becomes DW

Our alphabet series becomes AZ, BY, CX, DW

Hence, Option e) DW is correct.

Solved Question
• Select the letters that can replace the question marks (?) in the following series
• BF, CH, ?, HO, LT
• a) DN
• b) EL
• c) EK
• d) EM
• e) FJ

c) Ek

Show Solution

Let’s first convert letter cluster series into number series

BF, CH, ?, HO, LT becomes 2-6, 3-8, ?-?, 8-15, 12-20

After converting to number series, split this series into two series as follows:

Series I – 2 , 3 , ? , 8 , 12

Series II – 6 , 8 , ? , 15 , 20

Now these solve these two series separately.

Series I: 2 , 3 , ? , 8 , 12

In this series, we can see the difference between the first and second number is 1 and the difference between last and second last is 4. So, we can notice that the difference between adjacent numbers is increasing as 1, 2, 3, 4.

Therefore, the difference between the second number i.e, 3 and the next number should be 2. So, the missing number becomes 3+2 = 5. Also, cross-check if the difference between the fourth and fifth term is 3.

8 – 5 = 3, Yes the difference is 3.

so the series I now becomes 2 , 3 , 5 , 8 , 12.

Series II: 6 , 8 , ? , 15 , 20

In this series also, we can see the difference between the first and second number is 2 and the difference between last and second last is 5. So, we can notice that the difference between adjacent numbers is increasing as 2, 3, 4, 5.

Therefore, the difference between the second number i.e, 8, and the next number should be 3. So, the missing number becomes 8+3 = 11. Also, cross-check if the difference between the fourth and fifth term is 4.

15 – 11 = 4, Yes the difference is 4.

so the series II now becomes 6, 8, 11, 15, 20

Now merge these two series again, so our combined series becomes

2-6, 3-8, 511, 8-15, 12-20

Now convert this number series into alphabet series

5-11 becomes EK

2-6, 3-8, 511, 8-15, 12-20 becomes BF, CH, EK, HO, LT

Our alphabet series becomes BF, CH, EK, HO, LT

Hence, Option c) EK is correct.

#### Practice Problems

Question 1
1. Select the letters that can replace the question marks (?) in the following series.
2. CE, GI, KM, OQ, ?
3. a) TW
4. b) TV
5. c) SU
6. d) RT
7. e) UW
1. c) SU

Question 2
1. Select the letters that can replace the question marks (?) in the following series.
2. AD, EH, IL, ?, QT
3. a) LM
4. b) MN
5. c) MP
6. d) OM
1. c) MP

Question 3
1. Find the missing letter in the following series
2. JE, LH, OL, SQ, ?
3. a) WV
4. b) WX
5. c) VW
6. d) VX
7. e) XW
1. e) XW
Question 4
1. Select the letters that can replace the question marks (?) in the following series
2. CX, FU, IR, ?, OL, RI
3. a) LO
4. b) MN
5. c) NO
6. d) OP
7. e) OR
1. a) L, O

Question 5
1. Find the missing letters in the given series
2. DF, GJ, KM, NQ, RT, ?
3. a) UW
4. b) YZ
5. c) XZ
6. d) UX
7. e) YA
1. d) UX

### Type III – Series with Three Alphabets (Important)

These letter series questions are consists of series of two letter/alphabet arranged in a particular pattern.

Solved Question
• Select the letters that can replace the question marks (?) in the following series
• OTE, PUF, QVG, RWH, ?
• a) SYJ
• b) TXI
• c) SXJ
• d) SXI
• e) TYJ

d) SXI

Show Solution

Convert this letter cluster series into number series as follows

OTE, PUF, QVG, RWH, ? becomes 15-20-5, 16-21-6, 17-22-7, 18-23-8, ?

After converting to number series, split this series into three series as follows

Series I – 15, 16, 17, 18, ?

Series II – 20, 21, 22, 23, ?

Series III – 5, 6, 7, 8, ?

Now these solve these three series separately

Series I – this is a progression series with a common difference of 1, so the missing number becomes 18+1 = 19

15, 16, 17, 18, 19

Series II- This is also an increasing series with a common difference of 1, so the missing number becomes 23+1 = 24

20, 21, 22, 23, 24

Series III- This is also an increasing series with a common difference of 1, so the missing number becomes 8+1 = 9

5, 6, 7, 8, 9

Now, merge these three series again, so the combined series becomes

15-20-5, 16-21-6, 17-22-7, 18-23-8, 19249

Now convert this number cluster series into alphabet series

19249 becomes SXI

Our alphabet series becomes OTE, PUF, QVG, RWH, SXI

Hence, Option d) SXI is correct.

#### Practice Problems

Question 1
1. Select the letter- cluster that can replace the question mark (?) in the following series.
2. CXB, HUI, MRP, ROW, ?
3. a) WLD
4. b) VKD
5. c) WLK
6. d) VKC
1. a) WLD

Question 2
1. Select the letter- cluster that can replace the question mark (?) in the following series
2. EAC, GCE, IEG, ?
3. a) JHI
4. b) JGI
5. c) KGI
6. d) KHI
7. e) KIJ
1. c) KGI

Question 3
1. Select the letter- cluster that can replace the question mark (?) in the following series
2. KQG, JTK, HXO, ECS, ?
3. a) BIX
4. b) AIW
5. c) BIV
6. d) AHW
1. b) AIW

Question 4
1. Select the letter- cluster that can replace the question mark (?) in the following series
2. DAC, GWH, JSM, MOR, ?
3. a) PJV
4. b) QKV
5. c) PKW
6. d) QJW
1. c) PKW

Question 5
1. Select the letter- cluster that can replace the question mark (?) in the following series
2. AOS, CQU, ?, GUY, IWA
3. a) FSX
4. b) GSW
5. c) ESW
6. d) DRV
1. c) ESW

### Type IV – Series with Four Alphabets

These letter series questions are consist of a series of four-letter/alphabet arranged in a particular pattern. This type of question can be solved in a similar way type III questions are solved.

Solved Question
• Select the letter-cluster that can replace the question marks (?) in the following series
• ACDE, FHIJ, KMNO, ?
• a) PRST
• b) PQRS
• c) QRST
• d) QSTU

a) PRST

Show Solution

Convert this letter cluster series into number series as follows

ACDE, FHIJ, KMNO, ?  becomes 1-3-4-5, 6-8-9-10, 11-13-14-15, ?-?-?-?

After converting to number series, split this series into four series as follows

Series I – 1, 6, 11, ?

Series II – 3, 8, 13, ?

Series III – 4, 9, 14, ?

Series IV – 5, 10, 15, ?

Now these solve these four series separately

Series I – this is a progression series with a common difference of 5, so the missing number becomes 11+5 = 16

1, 6, 11, 16

Series II- This is also an increasing series with a common difference of 5, so the missing number becomes 13+5 = 18

3, 8, 13, 18

Series III- This is also an increasing series with a common difference of 5, so the missing number becomes 14+5 = 19

4, 9, 14, 19

Series IV- This is also an increasing series with a common difference of 5, so the missing number becomes 15+5 = 20

5, 10, 15, 20

Now, merge these four series again, so the combined series becomes

1-3-4-5, 6-8-9-10, 11-13-14-15, 16181920

Now convert this number cluster series into alphabet series

16181920 becomes PRST

Our alphabet series becomes ACDE, FHIJ, KMNO, PRST

Hence, Option a) PRST is correct.

#### Practice Problems

Question 1
1. Select the letter-cluster that can replace the question marks (?) in the following series.
2. CKDL, EKFL, GKHL, _ , KKLL
3. a) IJKL
4. b) IKJL
5. c) MNOP
6. d) MNPQ
1. b) IKJL

Question 2
1. Find the missing letter-cluster
2. AZCX, DWFU, GTIR, _ _ _ _
3. a) JRLO
4. b) JQLO
5. c) JRMO
6. d) JQMO
1. b) JQLO

Question 3
1. Find the missing letter-cluster
2. ABMN, EFQR, IJUV, _ _ _ _
3. a) KLYZ
4. b) LMXY
5. c) MNYZ
6. d) LMYZ
1. c) MNYZ

Question 4
1. Select the letter-cluster that can replace the question marks (?) in the following series
2. UVXY, PQST, KLNO, _ _ _ _, ABDE
3. a) FGHI
4. b) FGIJ
5. c) GHIJ
6. d) JIHG
1. b) FGIJ

Question 5
1. Find the missing letter-cluster
2. AFKP, BGLQ, CHMR, _ _ _ _
3. a) DINS
4. b) EINS
5. c) DJOT
6. d) EJOT
1. a) DINS

### Type V – Letter mix with Numbers

These type of series questions are consists of mix series of letter and numbers, arranged in a particular pattern.

Solved Question
• Select the letter-cluster that can replace the question mark (?) in the following series
• D-4, F-6, H-8, J-10, ?, ?
• a) K-12, M-13
• b) L-12, M-14
• c) L-12, N-14
• d) K-12, M-14

c) L-12, N-14

Show Solution

Our given series is D-4, F-6, H-8, J-10, ?, ?

Split the above series into two series i.e, the number and alphabet series as follows

Series I: Alphabet series – D, F , H, J, ?, ?

Series II: Number series – 4, 6, 8, 10, ?, ?

Now these solve these two series separately

Series I – Convert this alphabet series into number series

D, F , H, J, ?, ? becomes 4, 6, 8, 10, ?,?

After converting we can easily identify the missing terms because this is a progression series with common difference of 2, so the missing terms are

10+2 = 12,

12+2=14

So the series becomes

4, 6, 8, 10, 12, 14

Now convert it again to alphabet series

4, 6, 8, 10, 12, 14 becomes D, F, H, J, L, N

Series II- this a progression series with common difference of 2, so the missing terms are

10+2 = 12,

12+2 = 14

So the series becomes

4, 6, 8, 10, 12, 14

Now, merge these two series again, so the combined series becomes

D-4, F-6, H-8, J-10, L-12, N-14

Hence, Option c) L-12, N-14 is correct.

#### Practice Problems

Question 1
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. 3F, 6G, 11I, 18L, ?
3. a) 21O
4. b) 25N
5. c) 27P
6. d) 27Q
7. e) 25P
1. c) 27P

Question 2
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. KM5, IP8, GS11, EV14, ?
3. a) BX17
4. b) BY17
5. c) CY18
6. d) CZ17
7. e) CY17
1. e) CY17

Question 3
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. J2Z, K4X, I7V, ? , H16R, M22P
3. a) I11T
4. b) L11S
5. c) L12T
6. d) L11T
7. e) L12S
1. d) L11T

Question 4
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. 2Z5, 7Y7, 14X9, 23W11, 34V13, ?
3. a) 27U24
4. b) 47U15
5. c) 45U15
6. d) 47V14
1. b) 47U15
Question 5
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. Q1F, S2E, U6D, W21C,?
3. a) Y66B
4. b) Y44B
5. c) Y88B
6. d) Z88B
1. c) Y88B

### Type VI – Increasing Letter-cluster Series

In these type of series questions, the number of letter cluster increase in a particular pattern.

Solved Question
• Select the letter-cluster that can replace the question mark (?) in the following series
• AB, BA, ABC, CBA, ABCD
• a) ACBD
• b) BACD
• c) CABD
• d) DBAC
• e) DCBA

e) DCBA

Show Solution

In this question, first count the number of alphabets in one term

In above table, we can notice that the count of terms is increasing as 2, 2, 3, 3, 4, 4. So the missing term will have 4 alphabets.

Now try to observe the difference in adjacent terms,

Second term is written in reverse order of first.

Third and fourth terms have similar relationship as first and second terms

So we can divide the series in pairs as follows

AB, BA | ABC, CBA | ABCD, ?

Using the first and second pair relations, we can predict the relation between fifth and sixth term that is the Sixth term will reverse of fifth term that is DCBA.

Hence option e) DCBA is correct option.

#### Practice Problems

Question 1
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. AB, DEF, HIJK, ?, STUVWX
3. a) MNOPQ
4. b) LMNOP
5. c) LMNO
6. d) QRSTU
1. a) MNOPQ

Question 2
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. AF, BGL, CHMR, ?
3. a) EJOTY
4. b) DINSX
5. c) DINSY
6. d) EJOTX
1. b) DINSX

Question 3
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. X, VU, SRQ, ? , JIHGF
3. a) PONML
4. b) NMLK
5. c) ONML
6. d) NMKJ
1. c) ONML

Question 4
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. A, FG, KLM, ? , UVWXY
3. a) PORS
4. b) PQRS
5. c) QRST
6. d) ORST
1. b) PQRS

Question 5
1. Select the letter-cluster that can replace the question mark (?) in the following series
2. U, PQ, ? , FGHI, ABCDE
3. a) LMN
4. b) MNO
5. c) NOP
6. d) KLM
7. e) ONM
1. d) KLM

### Type VII – Repeating Letter Series

In these type of series questions, a series of small letters follow a certain pattern.

Solved Question
• Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series
• k _ lmml _ mk _ mmk _ lkkl _ m
• a) k,m, m, k, l
• b) l, k, m, k, k
• c) k, l, m, k, k
• d) k, l, k, l, m

d) k, l, k, l, m

Show Solution

Best way to solve to these question is fill the given blanks using each options one by one and see which option forms a particular pattern.

Option a) k,m, m, k, l

Let’s fill the blank spaces in the series with option (a)

k k lmml m mk m mmk k lkkl l m

We can notice that there is no particular logical pattern forming.

Option b) l, k, m, k, k

k l lmml k mk m mmk k lkkl k m

Using this option also no logical pattern is forming

Option c) k, l, m, k, k

k k lmml l mk m mmk k lkkl k m

Here, also no logical pattern forming

Option d) k, l, k, l, m

k k lmml l mk k mmk l lkkl m m

Here we can see a pattern of five letter is repeating in particular order.

kklmm | llmkk | mmkll | kklmm

Hence option d) k, l, k, l, m is correct.

Solved Question
• Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series
• _SWWS_WWWS_SWWWW_SSS
• a) W, S, S, S
• b) W, S, W, S
• c) W, W, S, S
• d) W, S, S, W

a) W, S, S, S

Show Solution

our given series is

_ SWWS _ WWWS _ SWWWW _ SSS

Now use every option one by one to identify which option forms logical pattern.

While looking for patterns try to form a group the letters. In general, patterns have of group of 2, 3, 4, and 5 in the series. In the previous example, it was a group of 5

Option a) Using this option our series becomes

W SWWS S WWWS S SWWWW S SSS

Now try to form group of 2, 3, 4, or 5 to identify pattern

We can notice a pattern in which the alternate letters are appearing with increasing group size as 2, 2, 3, 3, 4, 4.

W |S|WW|S S| WWW|S S S|WWWW| S SSS

Here we can see that a logical pattern is formed.

Hence option a) W, S, S, S is correct.

#### Practice Problems

Question 1
1. Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series
2. pq _ _ qpp _ _ pq _
3. a) ppppp
4. b) ppqpp
5. c) ppqpq
6. d) qppqq
1. b) ppqpp

Question 2
1. Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series
2. aab _ ab _ cabcca _ bcab _ c
3. a) bbbc
4. b) bbab
5. c) cabc
6. d) cbab
1. d) cbab

Question 3
1. Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series
2. c _ bba _ cab _ ac _ ab _ ca
3. a) abcbc
4. b) acbcb
5. c) babcc
6. d) bcacb
1. b) acbcb

Question 4
1. Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series
2. b _ b _ bb _ _ bbb _ bb _b
3. a) bbbbba
4. b) bbaaab
5. c) ababab
6. d) aabaab
1. c) ababab

Question 5
1. Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series
2. cab _ a _ c _ bc _ bc _ b _ ab
3. a) bcbbab
4. b) bcbbbc
5. c) acacab
6. d) cbaaac
1. d) cbaaac

## Letter Series Tricks, Shortcuts and Notes to Solve Alphabet Series Questions

1. Before solving letter series questions, quickly convert alphabets into number as follows

2. The second helpful table is with numbers in reverse order, but you don’t have to remember this table.

Just subtract 27 from the alphabet number from the above table.

For example:

The number for the letter ‘M’ in reverse order will be 27-13 = 14

The number for the letter ‘E’ in reverse order will be 27-5 = 22

3. In case of circular arrangement series, add 26 with the value.

For example:

Number for the letter ‘M’ in reverse order will be 26+13 = 39

Number for the letter ‘E’ in reverse order will be 26+5 = 31

4. In case of letter series questions that are consists of series of two or more letter/alphabet follow below steps to solve:

Step 1: Convert this letter cluster series into number series as follows

OTE, PUF, QVG, RWH,? ==> 15-20-5, 16-21-6, 17-22-7, 18-23-8, ?

Step 2: Split this series into multiple series

Series-I: 15, 16, 17, 18, ?     => ? = 19

Series-II: 20, 21, 22, 23, ?   => ? = 24

Series-III: 5, 6, 7, 8, ?            => ? = 9

Step 3: After solving these series separately merge them together

15-20-5, 16-21-6, 17-22-7, 18-23-8, 19-24-9

Step 4: Now again convert them to alphabet series

15-20-5, 16-21-6, 17-22-7, 18-23-8, 19-24-9 ==> OTE, PUF, QVG, RWH, SXI