Question 1

4, 6, 8, 9, 10, 11, 12

Accepted Answer

Each number is a composite number except 11.

Question 2

105, 85, 60, 30, 0, -45, -90

Accepted Answer

Subtract 20, 25, 30, 35, 40, 45 from successive numbers. So, 0 is wrong.

Question 3

5, 16, 6, 16, 7, 16, 9

Accepted Answer

Terms at odd places are 5, 6, 7, 8 etc. and each term at even place is 16. So, 9 is wrong.

Question 4

125, 127, 130, 135, 142, 153, 165

Accepted Answer

Prime numbers 2, 3, 5, 7, 11, 13 are to be added successively. So, 165 is wrong.

Question 5

46080, 3840, 384, 48, 24, 2, 1

Accepted Answer

The terms are successively divided by 12, 10, 8, 6, ...etc. So, 24 is wrong, it should be 8 (48/6 = 8).

Question 6

6, 13, 18, 25, 30, 37, 40

Accepted Answer

The differences between two successive terms from the beginning are 7, 5, 7, 5, 7, 5. So, 40 is wrong.

Question 7

36, 54, 18, 27, 9, 18.5, 4.5

Accepted Answer

The terms are alternatively multiplied by 1.5 and divided by 3. However, 18.5 does not satisfy it.

Question 8

56, 72, 90, 110, 132, 150

Accepted Answer

The numbers are 7 x 8, 8 x 9, 9 x 10, 10 x 11, 11 x 12, 12 x 13. So, 150 is wrong.

Question 9

25, 36, 49, 81, 121, 169, 225

Accepted Answer

The numbers are squares of odd natural numbers, starting from 5 up to 15. So, 36 is wrong.

Question 10

16, 33, 65, 131, 261, (....)

Accepted Answer

Each number is twice the preceding one with 1 added or subtracted alternatively. So, the next number is (2 x 261 + 1) = 523.

Question 11

10, 5, 13, 10, 16, 20, 19, (....)

Accepted Answer

There are two series (10, 13, 16, 19) and (5, 10, 20, 40), one increasing by 3 and the other multiplied by 2.

Question 12

1, 4, 9, 16, 25, 36, 49, (....)

Accepted Answer

Numbers are 12, 22, 32, 42, 52, 62, 72. So, the next number is 82 = 64.

Question 13

2, 4, 12, 48, 240, (....)

Accepted Answer

Go on multiplying the given numbers by 2, 3, 4, 5, 6. So, the correct next number is 1440.

Question 14

8, 7, 11, 12, 14, 17, 17, 22, (....)

Accepted Answer

There are two series (8, 11, 14, 17, 20) and (7, 12, 17, 22) increasing by 3 and 5 respectively.

Question 15

11, 13, 17, 19, 23, 29, 31, 37, 41, (....)

Accepted Answer

Numbers are all primes. The next prime is 43.

Question 16

8, 24, 12, 36, 18, 54, (....)

Accepted Answer

Numbers are alternatively multiplied by 3 and divided by 2. So, the next number = 54 � 2 = 27.

Question 17

2, 6, 12, 20, 30, 42, 56, (....)

Accepted Answer

The pattern is 1 x 2, 2 x 3, 3 x 4, 4 x 5, 5 x 6, 6 x 7, 7 x 8. So, the next number is 8 x 9 = 72.

Question 18

4, -8, 16, -32, 64, (....)

Accepted Answer

Each number is the proceeding number multiplied by -2. So, the required number is -128.

Question 19

7, 26, 63, 124, 215, 342, (....)

Accepted Answer

Numbers are (23 - 1), (33 - 1), (43 - 1), (53 - 1), (63 - 1), (73 - 1) etc. So, the next number is (83 - 1) = (512 - 1) = 511.

Question 20

5, 10, 13, 26, 29, 58, 61, (....)

Accepted Answer

Numbers are alternatively multiplied by 2 and increased by 3. So, the missing number = 61 x 2 = 122.

Odd Man Out and Series Questions