
Directions: In each of the following question, one term in the number series is wrong. Find out the wrong term.


1.

Find out the wrong number in the series
27, 81, 1331, 125

Answer: Option
C
Explanation:
Except 81 all are the perfect cubes.
27 = 3 ^{3}, 1331 = 11 ^{3}, 125 = 5 ^{3}
But
81 = 9 ^{2} is a perfect square.


2.

Find out the wrong number in the series.
17, 23, 31, 41, 53, 69

Answer: Option
D
Explanation:
Clearly, the correct sequence is:
17 
↘ 

↗ 
23 
↘ 

↗ 
31 
↘ 

↗ 
41 
↘ 

↗ 
53 
↘ 

↗ 


+6 

+8 

+10 

+12 

+14 




So, 69 is wrong term and must be replaced by 67.


3.

Find out the wrong number in the sequence
102, 101, 98, 93, 86, 74

Answer: Option
C
Explanation:
Clearly, the correct sequence is:
102 
↘ 

↗ 
101 
↘ 

↗ 
98 
↘ 

↗ 
93 
↘ 

↗ 
86 
↘ 

↗ 


–1 

–3 

–5 

–7 

–9 




So, 74 is wrong term and must be replaced by 77.


4.

Which one number is wrong in the given series?
126, 98, 70, 41, 14

Answer: Option
D
Explanation:
Clearly, the correct sequence is:
126 
↘ 

↗ 
98 
↘ 

↗ 
70 
↘ 

↗ 

↘ 

↗ 
14 

–28 

–28 

–28 

–28 




So, 41 is wrong and should be replaced by 42.


5.

Find out the wrong term in the given series of numbers.
22, 33, 66, 99, 121, 279, 594

Answer: Option
C
Explanation:
Except the number 279, all other numbers are completely divisible by 11.
121 
= 11; 
594 
= 54; 
11 
11 



