General Mental Ability

Series Completion Test

In this kind of test, series of numbers or letters is given. One of the units in the series (Either a number, a letter or a cluster of letters) is missing. The candidate is required to recognize the pattern of the series and to provide the missing digit or letter.

Type 1: Number Series

In each of the following questions, there is a series with one term missing as shown by (?) You have to find the missing number out of the five alternatives given below each question.

Ex1: 1  4  9  25  36  ?

(a). 49    (b). 18    (c). 20    (d). 7    (e). None of these

Ex1: (a): Clearly, the given series is the square of 1, 2, 3, 4, etc. Hence, the next number should be the square of 7, that is 49.

Ex:2. 212    179    146   113    ?

(a). 112     (b). 50     (c). 37     (d). 70     (e). 80

Ex 2: (e): In this series 33 is subtracted from each term to obtain the next term. so the next term is : 133 - 33 = 80

Ex 3:  17    36    53    68    ?    92

(a). 81      (b). 83      (c). 71      (d). 85      (e) None of these

Ex3: (a) : In this series the first number is added by 19 to obtain the second term and thereafter the number to be added to each term is decreased by 2. Thus 17 + 19= 36; 36 + 17=53;  53 +15=68;   68 + 13=81 and so on

Directions: In the following questions, each series contains a wrong term. You have to find out the wrong term.

Ex.4 :   3    10    19    31     43     58     75

Ex 4: (b): This series follows the pattern: 2² - 1, 3²+1,  4² +3, 5² + 5, and so on. According to this pattern, the fourth term should be 30 not 31.

Ex5:   325   259    202   160   127    105    94

Ex 5: (b): In this series each term is obtained by subtracting respectively 66, 55, 44, 33, 22 and 11 from the previous term. Hence 202 is wrong. The correct answer is 204.

Type II: Letter Series  

In these types of questions a few letters forming a series are given. The terms of the series may be formed by individual letters or clusters of letters. The sequence of letters follows a particular scheme. At one or at more places in the series one or some letters are missing. These missing letters are indicated by either a blank space or a mark of interrogation. You are required to study the scheme or pattern of the series of letters and supply the missing letter(S) out of the list of alternatives given below the series.

Ex 6:   C    B    A    E    D    Z    G    F    ?

        (a)  X      (b) H        (c) Q    (d) Y    (e) None

 Ex6: (d): In this series, the third, sixth, and ninth letters are in reverse alphabetical order.

Ex 7:   AK    EO    IS     ?     QA     UE

          (a) HY     (b) MW    (c) AE      (d) YZ     (e) None

Ex 7: (c) : In each term of the given series, the first letter is moved three steps forward while the second letter is moved thre steps backward in order to obtain the next term.

Ex 8:  AC    EG     IK    MO    ?

         (a)  QS     (b) DE     (c) HJ     (d) NP    (e) None of these

Ex 8: (a): Here one letter has been skipped between the letters of each term and also between the second letter of a term and the first letter of the next term.

Ex 9:   aaa  -  bb  -  aab  -  baaa  -  bb

       (a). babb      (b). abab      (c) bbaa   (d) baab    (e) None of these

Ex 9: (a) : The series is aaa  bbb  aaa  bbb  aaa  bbb

Ex 10:  HS    JQ    LO   NM    ?

(a) GH     (b) IJ      (c) OP    (d) KP     (e) PK

Ex 10: (e): In order to obtain the corresponding letters of the next term, the first latter of each term is moved two steps forward and the second letter is moved two steps backward.

                                                                Exercise

Directions—In each of the following questions one number-series is given in which one term is wrong. Find out the wrong term.

1.  5, 7, 11, 20, 35, 67.
(A) 11
(B) 20
(C) 35
(D) 67

2.  4, 11, 21, 34, 49, 69, 91.
(A)34
(B) 69
(C) 49
(D) 21

3.  5, 12, 19, 33, 47, 75, 104.
(A) 33
(B) 47
(C) 75
(D) 104

Directions—In each of the following questions a number series is given. Which one of the alternatives will replace the question mark (?)

4. 4, 9, 19, 39, 79, ?
(A)169
(B) 159
(C) 119
(D) 139

5. 0, 7, 26, 65, 124, 215, ?
(A) 305
(B) 295
(C) 342
(D) 323

6. 4, 7, 10, 10, 16, 13, ?
(A)19
(B) 23
(C) 21
(D) 22

7. 7, 12, 19, 28, 39, ?
(A) 52
(B) 50
(C) 51
(D) 48

8. 2, 11, 47, 191, 767, ?
(A) 2981
(B) 3068
(C) 3081
(D) 3058

Directions—In each of the following questions a series is given. Which one of the alternatives will replace the question-mark (?) ?

9. JD, KF, ? , PM, TR
(A) MI
(B) NJ
(C) NI
(D) OJ

10. BTO, DSQ, FRS, HQU, ?
(A) IPX
(B) JPW
(C) GPW
(D) JRW

11. B, D, G, K, P, ?
(A) U
(B) W
(C) T
(D) None of these

12. Z, T, O, K, H, ?
(A) E
(B) J
(C) F
(D) D

13. HZF, IWH, KSJ, NNL, ?
(A) SHM
(B) RHN
(C) THN
(D) RGM

14. MR, PO, SL, VI, ?
(A) YF
(B) ZE
(C) YD
(D) ZF

15. LOT, NNR, QMO, ULK, ?
(A) YKE
(B) YJF
(C) JKF
(D) JKE

16. CG, GH, LJ, RM, ?
(A) ZR
(B) YR
(C) ZQ
(D) YQ

17. FRP, HPQ. JNS, LLV, ?
(A) PKZ
(B) NJZ
(C) OJZ
(D) MKZ

18. Z15A, W13C, ?, Q9G, N7I.
(A) T12F
(B) R11F
(C) T11E
(D) R13D

19. MN, NM, MNO, ONM, MNOP, ?
(A) NPOM
(B) POMN
(C) MOPN
(D) PONM

20. CVD, CTE, DQE, DMF, EHF, ?
(A) ECG
(B) FCG
(C) EBG
(D) FBG

21. JKL, LKJ, JKLM, MLKJ, JKLMN, ?
(A) LMJKN
(B) NLMKJ
(C) NMUK
(D) NMLKJ

22. 7T19, 9Q16, 11N13, 13K10, 15H7, ?
(A) 17E4
(B) 18F5
(C) 17E3
(D) 18D4

Directions—In each of the following questions a letter-series is given, in which some letters are missing. The missing letters are given in the proper sequence as one of the alternatives. Find the correct alternative.

23. mno—p—no—p—n—opm.
(A) opmno
(B) pmomn
(C) pmmpn
(D) nmopo

24. ba—abab—b—ba—aba.
(A) abab
(B) aabb
(C) baab
(D) bbaa

25. —acca—ccca—acccc—aaa.
(A) caac
(B) ccaa
(C) acca
(D) caaa