REASONING - SERIES COMPLETION SET 01

Directions(1 to 15): In each of the following questions there is a series with one term missing as shown by (?). This term is given as one of the five alternatives given below the series.

1. 336  210  120    ?    24   60

(1) 40   (2) 50    (3) 60     (4) 70    (5) 80

2. 6  20  36  48  50  ?  0

          (1) 56    (2)50    (3)46   (4) 40    (5) 36

3. 2  6 12   20  30  42   ?

          (1) 48    (2) 56    (3)60  (4)64    (5)70

4. 2  ?  6  8  12  15  20

(1)  3    (2)  4    (3)  5  (4)  6    (5)  8

5. 1 8 9   ?   25   216   49

(1)  60    (2)  64    (3)  70   (4 ) 75    (5)  81

6. 2   3  7  11  ?  17

(1)  12    (2)  13    (3)  14       (4)  15      (5)  16

7. 5  11  17  ?  31   41

(1)  19    (2)  21     (3)  23      (4)  25    (5)  27

    8.  7  13  21  ?  43  57

(1)  27    (2)  29    (3)  31    (4)  35    (5)  41

9. 3  15  35  ?  143

          (1)  63    (2)  69    (3)  77    (4)  81    (5)  85

10. 2  1  2   4   4   5   6   7   8   9   10   11  ?

(1)  9    (2)  10    (3)  11      (4)  12   (5)  13

11. 1  3  6  10  15  ?   28  36

(1)  20    (2)  21    (3)  23   (4)  24    (5)  25

12. 1  5  9  ?  25  37  49  65

(1)   11    (2)  13    (3)  15   (4)   17   (5)    18

13. 0  2  6   12  20  30  42  ?

(1)  50     (2)  52    (3)  54    (4)  55    (5)  56

14. 7  17  31  49  ?  97  127

(1)  59    (2)  61    (3)  71  (4)  87    (5)   91

15. 0  3  8  15  24  35  48  ?

(1)  51    (2)  55    (3)  56   (4)  61    (5)  65

Answer and Explanations:

1. (3) : Different terms of the given series are 7^{3 –} 7, 6³-6, 5³-5, 4³-4, 3³-3, 2³-2 and   1³-1

2. (5) : 1st term+3rd term/2(-1) = Second term

          2nd term+4rd term/2(+2) = Third  term

          3^rd term+5rd term/2(+5) = Fourth  term,  And so on.

3. (2) : Different terms of the given series are 1²+1, 2²+2, 3²+3, 4²+4, 5²+5, 6 ²+6 and 7²+7
4. (1) : Alternative terms of the given series from two different series :        I : 2 6 12 20            II : 3 8 15
5. (2) : : Alternative terms of the given series from two different series :      I : 1², 3², 5², 7²       II : 2³, 4³, 6³

6. (2) : The given series consists of prime numbers only.
7. (3) : The given series consists of alternate prime numbers starting from the prime number 5.
8. (3) : The sequence in the given series is +6,+8,+10,+12,+14.
9. (1) : The terms of the given series are 2²-1,4²-1,6²-1,8²-1,10²-1 and 12²-1.
10. (2) : The given series is made up of the following three series such that 1^st, 4^th, 7^th, 10^th and 13^th terms form 1^st series;2^nd, 5^th, 8^th and 11^th terms form 2^nd series and 3^rd, 6^th, 9^th and 12^th terms form 3^rd series:

          Series I : 2, 4, 6, 8, 10     Series II : 1, 4, 7, 10    Series III : 2, 5, 8, 11

11. (2) : The sequence in the given series is |+2, +3, =4, +5, +6, +7, +8.
12. Alternative terms form two different series :

Series I : 1,9, 25, 49
Series II : 5, 17, 37, 65
Different terms in series I are 1,3,5,7 respectively and different terms in series II are 2²+1,4²+1,6²+1,8²+1 respectively.

13. (5) : The sequence in the given series is =2,+4,+6,+8,+10,+12,+14.
14. (3) : The sequence in the given series is +10, +14, +18, +22,+26,+30.
15. (4) : Different terms of the given series are 1²-1,2²-1,3²-1,4²-1,5²-1,6²-1,7²-1 and 8²-1 respectively.