Aptitude - Odd Man Out and Series

Exercise :: Odd Man Out and Series - Find Wrong No.

Find out the wrong number in the series.
1. 

7, 8, 18, 57, 228, 1165, 6996

A. 8
B. 18
C. 57
D. 228
E. 1165

Answer: Option D

Explanation:

Let the given numbers be A, B, C, D, E, F, G.

Then, A, A x 1 + 1, B x 2 + 2, C x 3 + 3, D x 4 + 4, E x 5 + 5, F x 6 + 6 are the required numbers.

Clearly, 228 is wrong.


2. 

1, 1, 2, 6, 24, 96, 720

A. 720
B. 96
C. 24
D. 6
E. 2

Answer: Option B

Explanation:

Go on multiplying with 1, 2, 3, 4, 5, 6 to get next number.

So, 96 is wrong.


3. 

196, 169, 144, 121, 100, 80, 64

A. 169
B. 144
C. 121
D. 100
E. 80

Answer: Option E

Explanation:

Numbers must be (14)2, (13)2, (12)2, (11)2, (10)2, (9)2, (8)2.

So, 80 is wrong.


4. 

445, 221, 109, 46, 25, 11, 4

A. 221
B. 109
C. 46
D. 25
E. 11

Answer: Option C

Explanation:

Go on subtracting 3 and dividing the result by 2 to obtain the next number.

Clearly, 46 is wrong.


5. 

190, 166, 145, 128, 112, 100, 91

A. 100
B. 166
C. 145
D. 128
E. 112

Answer: Option D

Explanation:

Go on subtracting 24, 21, 18, 15, 12, 9 from the numbers to get the next number.

190 - 24 = 166
166 - 21 = 145
145 - 18 = 127 [Here, 128 is placed instead of 127]
127 - 15 = 112
112 - 12 = 100 ... and so on.

Therefore, 128 is wrong.