Aptitude - Odd Man Out and Series - Discussion

Find out the wrong number in the given sequence of numbers.

12. 

6, 13, 18, 25, 30, 37, 40

[A]. 25
[B]. 30
[C]. 37
[D]. 40

Answer: Option D

Explanation:

The differences between two successive terms from the beginning are 7, 5, 7, 5, 7, 5.

So, 40 is wrong.


Shubham said: (Sep 9, 2010)  
Here the following also applies.

The first term is 6*1=6.

The 2nd term is 6*2=12+1=13.

The 3rd term is 6*3=18.

6*4=24+1=25.

So the next should be42 so 40 is incorrect.

Ashwini said: (Jul 6, 2012)  
Alternatively 7 and 5 are added from the term.

6+7=13.
13+5=18.
18+7=25.
25+5=30.
30+7=37.
37+5=42.

So, 40 is wrong.

Tarunteja said: (Aug 19, 2012)  
As that given series

6, 13, 18, 25, 30, 37, 40

the even terms 13,25,37 these are in form adding's of 12
13+12=25
25+12=37
37+12=49 but 49 hasn't mentioned in the series we can leave even plces series
coming to odd series
6,18,30,40
these are mutilples of 6 with add numbers of thier places
6*1=6
6*3=18
6*5=30
the next series should 6*7=42 instead they given 40.
so by this we can say 40 should be odd one out

Tarun said: (Dec 20, 2012)  
One more solution can be
there are two series one starting from 6,18,30,...
and another starting from 13,25,37,...
as we can clearly see that these two series follow the same logic of adding 12 to the existing term to obtain the next term.
This goes like this...
6
6+12=18
18+12=30
30+12=42
....
....

and the other one as
13
13+12=25
25+12=37
37+12=49
....
....

Aditya Kadam said: (Mar 22, 2014)  
I used different logic and answer is same.

Consider 1st, 3rd, 5th and 7th term.

1st- 6*1 = 6.
3nd- 6*3 = 18.
5rd- 6*5 = 30.
7th- 6*7 = (42).

And in 2nd 4th and 6th term. successively add 12.

So thats why 40 is odd one out.

Santosh said: (Aug 13, 2014)  
6+6 = 12+1 = 13.
13+6 = 19-1 = 18.
18+6 = 24+1 = 25.
25+6 = 31-1 = 30.
30+6 = 36+1 = 37.
37+6 = 43-1 = 42.

So, 40 is wrong.

Govind said: (Sep 23, 2014)  
I agree with above explanations but 25 could be an odd number because in a given series only 25 is perfect square.

So either 25 or 40 is an odd number.

Indumati Parida said: (Aug 26, 2015)  
6 = 1*6.
13 = 2*6+1.
18 = 3*6.
25 = 4*6+1.
30 = 5*6.
37 = 6*6+1.
42 = 7*6.

But the last one is 40.

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