# Aptitude - Odd Man Out and Series - Discussion

### Discussion :: Odd Man Out and Series - Missing No. (Q.No.10)

Insert the missing number.

10.

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

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

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.