Aptitude - Odd Man Out and Series - Discussion

Insert the missing number.

10. 

7, 26, 63, 124, 215, 342, (....)

[A]. 481
[B]. 511
[C]. 391
[D]. 421

Answer: Option B

Explanation:

Numbers are (23 - 1), (33 - 1), (43 - 1), (53 - 1), (63 - 1), (73 - 1) etc.

So, the next number is (83 - 1) = (512 - 1) = 511.


Bhupinder Singh said: (Jan 18, 2011)  
I have soved it in a different way like:

7, 2+6=8, 6+3=9, 1+2+4=7, 2+1+5=8, 3+4+2=9, (4+2+1=7 or 5+1+1=7)
so the series is 7,8,9,7,8,9,7 ....

Please reply me can we apply this logic here or not

Venki said: (Aug 19, 2012)  
No. Because here only one answer has taken. Logic is ok. But apply every time.

Ffd said: (Sep 28, 2014)  
I too in same way and that is also the possible way.

Princess said: (Jan 7, 2015)  
@Bhupinder Singh.

Your logic is not working here as the sum of digits of option D (421) is 4+2+1=7, than how we can say the answer is B?

Jagadeesh Garimella said: (Aug 31, 2016)  
There is one more way but lengthy:

26 - 7 = 19,
63 - 26 = 37,
124 - 63 = 61,
215 - 124 = 91,
342 - 215 = 127:.

If we take the remainders and subtract,
37 - 19 = 18,
61 - 37 = 24,
91 - 61 = 30
127 - 91 = 36 which are multiples of 6, hence the last number should have the difference of 42.

Hence 127 + 42 =169. This should be added to 342 to get the answer.

Jyoti Yadav said: (Sep 26, 2018)  
1 2 9 37 65 126 217 ?

Please solve the given series with the correct explanation.

Hritik said: (Jun 11, 2019)  
@Jyoti Yadav.

Cube of 0+1=1.
Cube of 1+1=2.
Cube of 2+1=9.

But there is no any cube for 37.
Cube of 4+1=65,
Cube of 5+1=126.
Cube of 6+1=217.

That's why 37 is odd in this group.

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