Alphabet series consists of letters of the alphabet placed in a specific pattern. If you keep in your mind the order of the letters with their respective numbers it will help you answer the questions quickly above alphabet series:

E.g.:  what will be the next term in
BKS, DJT, FIU, HHV, ?
(1) IJX
(2) IGX
(3) JGW
(4) IGU
(5) JGU

Answer: (3). In each term, the first letter is moved two steps forward, the second letter one step backward and the third letter one step forward to obtain the corresponding letter of the next term. So, the missing term is JGW.

LETTER SERIES

This type of question usually consists of a series of small letters which follow a certain pattern. However some letters are missing from the series. These missing letters are then given in a proper.sequence as one of the alternatives. The candidate is required to choose this alternative as the answer:

E.g.: aab_aaa_bba_
(1) baa
(2) abb
(3) bab
(4) aab
(5) bbb

-: Practice Test :-

In each of the following questions, various terms of a letter series are given with one term missing. Choose the missing term out of the given alternatives.
Q.1) cmw, hrb, ——, rbl, wgq, blv

(1) mwg
(2) lvf
(3) lwg
(4) mxg
(5)wmx

Q.2) DKY FJW HIU JHS ——
(1) KGR
(2) LFQ
(3) KFR
(4) LGQ
(5) None of these
Q.3). —— siy oeu kaq gwm csi
(1) wne
(2) wnb
(3) vne
(4) vme
(5) None of these
Q.4) BXJ ETL HPN KLP ——
(1) NHR
(2) MHQ
(3) MIP
(4) NIR
(5) None of these
Q.5) QPO, SRQ, UTS, WVU, ——
(1) XVZ
(2) ZYA
(3) YXW
(4) VWX
(5) AZY
Q.6) P3C, R5F, T8I, V12L, ——
(1) Y17O
(2) X17M
(3) X17O
(4) X16O
(5) None of these
Q.7) D-4, F-6, H-8, J-10, ——, ——
(1) K-12, M-13
(2) L-12, M-14
(3) L-12, N-14
(4) K-12, M-14
(5) K-12, N-14
Q.8) G, H, J, M, ——, V
(1) T
(2) S
(3) R
(4) U
(5) Q
Q.9) OTE PUF QVG RWH ——
(1) SYJ
(2) TXI
(3) SXJ
(4) SXI
(5) QWD
Q.10) BD GI LN QS ——
(1) TV
(2) VW
(3) WX
(4) WY
(5) VX
Directions(Q.11 to 15): In each of the following letter series, some of the letters are missing which are given in that order as one of the alternatives below it. Choose the correct alternative.
Q.11) ba_ba_bac_acb_cbac
(1) aacb
(2) bbca
(3) ccba
(4) cbac
(5) None of these
Q.12) adb_ac_da_cddcb_dbc_cbda
(1) bccba
(2) cbbaa
(3) ccbba
(4) bbcad
(5) None of thes
Q.13) a_ba_cbaac_aa_ba
(1) ccbb
(2) cabc
(3) cbcb
(4) bbc
(5) None of these
Q.14) bc bb_aabc (1) acac (2) babc (3) abab (4) aac (5) None of these Q.15) b – b – bb – – bbb – bb – b (1) bbbbba (2) bbaaab (3) ababab (4) aabaab (5) None of these  Directions(Q.16 to 30): In each of the following letter series, some of the letters are missing which are given in that order as one of the alternatives below it. Choose the correct alternative Q.16) b_cd_d_bcc_cdb (1) dbbbc (2)dccbd (3)bddcb (4)beccb (5) None of these  Q.17) a b _b_cbacba_ba_cabcb (1)bccb (2)acbc (3)caba (4)cbbb (5) None of these  Q.18) ac_c_cb_acbcacbca_bc (1)abbb (2)bacc (3)babc (4)bbcc (5) None of these  Q.19) a_c_baab_cb
(1) bcca
(2)abbc
(3)abab
(4)aabb
(5) None of these
Q.20) ab_ c c_ffe (1) dadde (2)baded (3)abdee (4)abcde (5) None of these Q.21) _b c a b c a b c _ a b c a_ b
(1) a b a c
(2)a b c a
(3)a a b c
(4)b b c a
(5) None of these
 Q.22) b_ab_b_a a b _ b
(1)a a b b
(2)a b b b
(3)a b b a
(4) b a a
(5) None of these
 Q.23) bc, cde ,de, efg, fg, ?
(1)ijk
(2)ghi
(3)fgh
(4)hij
(5) None of these
 Q.24) a _ _ b abba a bb a b a
(1) abab
(2)abba
(3)aabb
(4)aaab
(5) None of these
 Q.25) ab _ babc_ ab_ b _ bcb_ b
(1)c b c a a
(2)c a b a c
(3)a b c b a
(4) a c a c a
(5)  None of these
 Q.26) a_ ba_c_aad_aa_ea
(1) babbd
(2)babbc
(3)babba
(4)bbba
(5) None of these
 Q.27) b_ccacca_ba_bbc_bc_a
(1) acbca
(2)bacab
(3)baabc
(4)abaaa
(5) None of these
 Q.28) b_ccacca_ba_bbc_bc_a
(1) acbca
(2)bacab
(3)baabc
(4)abaaa
(5) None of these
 Q.29) ab_bbc_c _ ab_ ab _ c
(1) bccab
(2)cacab
(3)cacac
(4)cbabc
(5) None of these
Q.30) tu_rt_s _ usrtu
(1) rsurts
(2)rtusru
(3)rsutrr
(4)rsurtr
(5) None of these
 Directions(Q.31 to 50): In each of the following letter series, some of the letters are missing which are given in that order as one of the alternatives below it. Choose the correct alternative
Q.31) ABC, PQR, DEF, STU,    ?                                       
(1) IJK
(2) GKL
(3) VWX
(4) GHI
(5) None of these
Q.32) AMDN, GMJN, ?, RMUN
(2) MMPN
(3) OMRN
(4) ONSU
(5) None of these
Q.33)NMT, POV, ROX,?
(1) TSZ
(2)TPZ
(3)TSY
(4)TRZ
(5) None of these
Q.34) HFD, BZX, VTR,?
(1) TRP
(2) KIH
(3) PNL
(4) GEC
(5) None of these
Q.35) C -3, E – 5, G – 7, I- 9, ?,
(1) M -18, K- 14
(2) X-24, M-21
(3) K- 11, M-13
(4) O – 15, X – 24
(5) None of these
Q.36) AFI, JOR, MRU,?                                                         
(1)RJL
(2)GJN
(3) HMP
(4)PMO
(5) None of these
Q.37) ELFA, GLHA, ILJA,?, MLNA
(1) OLPA
(2)KLMA
(3) LLMA
(4)KLLA
(5) None of these
 Q.38) FGHJKLNOPRS?                                         
(1) T
(2)M
(3)Q
(4)U       
(5) None of these
 Q.39) X, Q, K, F,?                                         
(1) B
(2)C
(3)D
(4)E       
(5) None of these
Q.40) BEAG, DGCI, FIEK, ?
(1) HKGM
(2)HGKJ
(3)HKLJ
(4)HMIE
(5) None of these
 Q.41) ABEF, IJMN, ?
(1) QRVU
(2)QRUV
(3)QRVW
(4)QSVU
(5) None of these
Q.42)  KJL, ONP, SRT, ?
(1)WVX
(2)VWX
(3)WXV
(4)VUW
(5) None of these
Q.43)  AN, BO, CP, DQ, ?
(1)EG
(2)ER
(3)EH
(4)EF
(5) None of these
Q.44) PBD, REH, THL, ?
(1)UVW
(2)MNO
(3)UVX
(4)VKP
(5) None of these
Q.45)  ML, NO, KJ, PQ, IH, ?
(1)RS
(2)GI
(3)RH
(4)RK
(5) None of these
Q.46) Y X Z X W Y W V X V _ _
(1)U W
(2)VW
(3)VU
(4)WU
(5) None of these
Q.47)  b- 0, y-3, c- 8, x – 15, d-24, ?
(1)  e-48
(2) w-35
(3) w – 39
(4) v-30
(5) None of these
Q.48)  AZ,CX, FU, ?
(1)IR
(2)IV
(3)JQ
(4)KP
(5) None of these
Q.49)  ELFA, GLHA, ILJA, ? ,MLNA
(1)KLMA
(2)KLLA
(3)OLPA
(4)LLMA
(5) None of these
 Q.50) ACE, BDF, CEG, ?
(1)DEH
(2)DFE
(3)DEF
(4)DFH
(5) None of these

Answers
1) 1 2)4 3)5 4)1 5)3 6)3 7)3 8)5 9)4 10)5
11)3 12)2 13)2 14)1 15)3 16)3 17)3 18)4 19)2 20)1
21)1 22)2 23)2 24)1 25)1 26)3 27)3 28)3 29)3 30)1
31)4 32)2 33)1 34)3 35)3 36)3 37)4 38)1 39)1 40)1
41)2 42)1 43)2 44)4 45)1 46)1 47)3 48)2 49)4 50)4