Number series

1)2, 7, 14, 23, ?, 47 

A.    31

B.    28

C.    34

D.    38

Answer : C.

The given sequence is +5, +7, +9, —— 
ie. 2+ 5 = 7, 7 + 7 = 14, 14 + 9 = 23
Missing Number = 23 + 11 = 34.

2) 4, 6, 12, 14, 28, 30, ? 

 A.    32

 B.    64

 C.    62

 D.    60

Answer : D.

The given sequence is a combination of two series 4, 12, 28, .... and 6, 14, 30, .... The pattern is +8, +16, +32. So, the missing number = (28 + 32) = 60

3) 4, 9, 13, 22, 35, ? 

A.    57

 B.    70

 C.    63

 D.    75

Answer : A

Sum of two consecutive numbers of the series gives the next number.

4) 11, 13, 17, 19, 23, 29, 31, 37, 41, ? 

A.    43

B.    47

C.    51

 D.    53

Answer : A.

The series consists of prime numbers.

5) 15, 31, 63, 127, 255, ? 

 A.    513

 B.    511

C.    523

 D.    517

Answer : B.

Each number is double of the preceding one plus 1.

6) 5, 11, 17, 25, 33, 43, ? 

A.    49

B.    51

C.    52

 D.    53

Answer : D.

The sequence is +6, +6, +8, +8, +10, ....

7) 9, 12, 11, 14, 13, ?, 15 

 A.    12

B.    16

C.    10

D.    17

Answer : B.

Alternatively, 3 is added and one is subtracted.

8) 0.5, 0.55, 0.65, 0.8, ? 

A.    0.7

B.    0.9

C.    0.95

 D.    1

Answer : D.

The pattern is + 0.05, + 0.10, + 0.15, .....

9) 1, 4, 9, 16, 25, ? 

A.    35

 B.    36

C.    48

 D.    49

Answer : B.

The sequence is a series of squares, 1², 2², 3², 4², 5²....

10) 2, 1, (1/2), (1/4), ? 

A.    (1/3)

 B.    (1/8)

 C.    (2/8)

 D.    (1/16)

Answer : B.

This is a simple division series; each number is one-half of the previous number.