Aptitude - Odd Man Out and Series - Discussion

The answer can be solved out in two ways:

1) The series is continued by first squaring the numbers from 1 and then next we have to add one the squared numbers and so on. By which 64 is the only number in the series written without adding 1 to it after squared.

2) We can also solve in the another way. Add the subsequent odd numbers from 3 to the given series but we find 65 is obtained in place of 65 by adding 15 to 50.

Therefore it can be judged that 64 is the odd man out.

Its very simple just follow this, just go on subtracting.

2, 5, 10, 17, 26, 37, 50, 64.

5-2=3.
10-5=5.
17-10=7.
26-17=9.
37-26=11.
50-37=13.

But 64-50 is equal to 14. We have seen that the order is 3, 5, 7, 9, 11, 13.

All are odd numbers but 14 is an even number. So finally the answer is 64.

Odd place even no, even place odd no. But 64 is even.

Addition of prime number to previous digit.

3, 5, 7, 9, 11, 13.

Difference between each number is odd like 3, 5, 7, 9. And last two numbers difference is even.

Difference between 2 and 5 is 3, similarly difference 5 and 10 is 5.

Difference between 10 and 17 is 7, similarly difference between 17 and 26 is 9, difference between 26 and 37 is 11, difference between 37 and 50 is 13, difference between 50 and 64 is 14 (it is an odd one which have to ruled out).

So we have to add 3 5 7 11 13 15.

Only 64 is perfect square.

In between 2and 5 there are two numbers i.e., 3, 4.

Similarly 5 and 10 there are four numbers i.e., 6, 7, 8, 9.

Between 10 and 17 there are six numbers i.e., 5, 11, 12, 13, 14, 15, 16.

Similarly, the order is increased like 2, 4, 6, 8, 10, 12, 14.

But the last two numbers 50 and 64 there are only 13 numbers.

So the answer is 64.

2 + 3 = 5.
5 + 5 = 10.
10 + 7 = 17.
And so on.

Each number has difference of odd numbers 3, 5, 7, 9, 11, 13.