Aptitude - Odd Man Out and Series

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

Find out the wrong number in the series.
6. 

19, 26, 33, 46, 59, 74, 91

A. 26
B. 33
C. 46
D. 59
E. 74

Answer: Option B

Explanation:

Go on adding 7, 9, 11, 13, 15, 17 respectively to obtain the next number.

So, 33 is wrong. It must be 35


7. 

1, 3, 10, 21, 64, 129, 356, 777

A. 10
B. 21
C. 64
D. 129
E. 356

Answer: Option E

Explanation:

A x 2 + 1, B x 3 + 1, C x 2 + 1, D x 3 + 1 and so on.

So, 356 is wrong.


8. 

6, 12, 48, 100, 384, 768, 3072

A. 768
B. 384
C. 100
D. 48
E. 12

Answer: Option C

Explanation:

Each even term of the series is obtained by multiplying the previous term by 2.

2nd term = (1st term) x 2 = 6 x 2 = 12

4th term = (3rd term) x 2 = 48 x 2 = 96.

6th term = (5th term) x 2 = 384 x 2 =768.

4th term should be 96 instead of 100.


9. 

40960, 10240, 2560, 640, 200, 40, 10

A. 640
B. 40
C. 200
D. 2560
E. 10240

Answer: Option C

Explanation:

Go on dividing by 4 to get the next number.

So, 200 is wrong.


10. 

3, 7, 15, 39, 63, 127, 255, 511

A. 7
B. 15
C. 39
D. 63
E. 127

Answer: Option C

Explanation:

Go on multiplying 2 and adding 1 to get the next number.

So, 39 is wrong.