Find out the wrong number in the following series: 5, 15, 30, 80, 180, 540, 1080

Correct Answer: 165

Explanation:

The given series follow the rule that :

Multiplying consecutive prime numbers
2,3,5,7,11,13,17,19....
2x3 = 6
3x5 = 15
5x7 = 35
7x11 = 77
11x13 = 143
13x17 = 221
So, the wrong term is 165.

Correct Answer: 21, 15, 23

Explanation:

Given number series is 9 17 11 19 13 

Here the pattern is

• 9

• 9 + 8 = 17

• 17 - 6 = 11

• 11 + 8 = 19

• 19 - 6 = 13

• 13 + 8 = 21

• 21 - 6 = 15

• 15 + 8 = 23

Correct Answer: 36 & 90

Explanation:

the next 2 number in series we need to divide the series into 2 different series

First series : 4 , 6, 12, 30 ??

Second Series : 12,18,26, ??

So we need to see for the pattern for those series in order to find the next two number , we can do this by finding the difference or division , multiplication logic whatever may apply :

 

• Pattern of Series 1 :

 

6 divide 4 : 1.5

Next number i.e 12 divided by 6=2

Next number i.e 30 divided by 12 =2.5

So series is going in multiples of 1.5, 2, 2.5, 3 , so on

So first series will look like

4 , 6, 12, 30, 30x3 =90

 

• Pattern of Series 2 : 12,18,26, ??

 

Its simple Adding numbers with iterative logic (i.e 6, 8, then followed by 10, 12)

Series will be like 12,18,26,36.

 

For the next two numbers : Series will be like 4, 12, 6, 18, 12, 26, 30, 36, 90

Correct Answer: 256 & 3125

Explanation:

The above given sequence follows a pattern that,

 

$$\begin{gathered} 1 \\ 2 2 = 4 \\ 3 3 = 27 \\ 4 4 = 256 \\ 5 5 = 3125 \\ 6 6 = 46656 \\ and so on . . . \end{gathered}$$

Therefore, the next two numbers in the given sequence is 256 & 3125.

Correct Answer: 91.12

Explanation:

Given number series is 12  9  13.5  30.3  ?  341.7

Here the pattern followed by the series is

12 

12 x 0.75 = 9

9 x 1.5 = 13.5

13.5 x 2.25 = 30.3

30.37 x 3 = 91.12

91.12 x 3.75 = 341.71

 

Hence, the missing number in the sequence is 91.12.

Correct Answer: 8

Explanation:

Given number series follows a pattern that,

2

2 x 1.5 + 1 = 4

4 x 1.5 + 1 = 7 (not equal to 8)

7 x 1.5 + 1 = 11.5

11.5 x 1.5 + 1 = 18.25

18.25 x 1.5 + 1 = 28.375

 

Hence, the odd number in the given number series is 8.

Correct Answer: 392

Explanation:

The given number series 11, 13, 30, 96, ? follows a pattern that,

11

11 x 1 + 2 = 13

13 x 2 + 4 = 30

30 x 3 + 6 = 96

96 x 4 + 8 = 392

 

Hence, the next number in the given series is 392.

Correct Answer: 40

Explanation:

The given number series is 5, 8, 40, 90, 664

5

5 - 1 x 2 = 8

8 - 3 x 4 = 20 (NOT 40)

20 - 5 x 6 = 90

90 - 7 x 8 = 664

Correct Answer: 203

Explanation:

The given number series is 125,   138,   164,   ?,   255

 

125

 

125 + 13x1 = 138

 

138 + 13x2 = 164

 

164 + 13x3 = 203

 

203 + 13x4 = 255

 

 

 

Hence, the missing number in the series is 203.

Correct Answer: 72

Explanation:

With close observation, you will note that each number in the list is in the middle of two prime numbers. Thus:

4 is in the middle of 3 and 5, 6 is in the middle of 5 and 7, 12 is in the middle of 11 and 13, 18 is in the middle of 17 and 19, 30 is in the middle of 29 and 31. 42 is in the middle of 41 and 43, 60 is in the middle of 59 and 61.

Therefore, the next number would be the one that is in the middle of the next two prime numbers, which is 72 (which is in the middle of 71 and 73).