Aptitude - Odd Man Out and Series

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

Find out the wrong number in the series.
11. 

64, 71, 80, 91, 104, 119, 135, 155

A. 71
B. 80
C. 104
D. 119
E. 135

Answer: Option E

Explanation:

Go on adding 7, 9, 11, 13, 15, 17, 19 respectively to obtain the next number.

So, 135 is wrong.


12. 

15, 16, 34, 105, 424, 2124, 12756

A. 16
B. 34
C. 105
D. 424
E. 2124

Answer: Option E

Explanation:

2nd term = (1st term) x 1 + 1 = 15 x 1 + 1 = 16.

3rd term = (2nd term) x 2 + 2 = 16 x 2 + 2 = 34.

4th term = (3th term) x 3 + 3 = 34 x 3 + 3 = 105.

5th term = (4th term) x 4 + 4 = 105 x 4 + 4 = 424

6th term = (5th term) x 5 + 5 = 424 x 5 + 5 = 2125

6th term should 2125 instead of 2124.


13. 

10, 26, 74, 218, 654, 1946, 5834

A. 26
B. 74
C. 218
D. 654
E. 1946

Answer: Option D

Explanation:

2nd term = (1st term) x 3 - 4 = 10 x 3 - 4 = 26.

3rd term = (2nd term) x 3 - 4 = 26 x 3 - 4 = 74.

4th term = (3th term) x 3 - 4 = 74 x 3 - 4 = 218.

5th term = (4th term) x 3 - 4 = 218 x 3 - 4 = 650.

5th term must be 650 instead of 654.


14. 

2880, 480, 92, 24, 8, 4, 4

A. 480
B. 92
C. 24
D. 8
E. 4

Answer: Option B

Explanation:

Go on dividing by 6, 5, 4, 3, 2, 1 respectively to obtain the next number.

Clearly, 92 is wrong.


15. 

3, 7, 15, 27, 63, 127, 255

A. 7
B. 15
C. 27
D. 63
E. 127

Answer: Option C

Explanation:

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

So, 27 is wrong.


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