Aptitude - Odd Man Out and Series - Discussion

Here 11 is only the prime number in the numbers given above.

All other numbers 4, 6, 8, 10, 12 are divisible by 2, and number nine is divisible by 3 so these are not the prime numbers.

Hence, "11" is the odd one here.

11 is the prime number.

It's about sequence as +2,+2,+1,+1,+2,+2,...So on

4+2=6
6+2=8
8+1=9
9+1=10
10+2=12......And so on
Hence there is no place for 11. So it is the odd one.

Here the logic is;

Consider 4,8,10 and 12. They are divisible by 2. Now consider 6,9 and 11. 6 and 9 are divisible by 3 but 11 can't be divided by 3.

So the answer is 11.

11 is correct because 11 is the prime number.

Simple 11 is prime number cannot multiple with any number.

11 is a prime number.

What about 9?

As per my point of view, the answer is 9.
Because,
2 * 2 = 4,
2 * 3 = 6,
2 * 4 = 8,
2 * 5 = 10, instead of 9 here 10 came so my answer is 9. Am I right?

{2*2=4, 4*1=4, 1*4=4}.....>.....4.

{3*2=6, 2*3=6, 6*1=6, 1*6=6}.....>.....6.

{4*2=8, 2*4=8, 8*1=8, 1*8=8}.....>.....8.

{3*3=9, 9*1=9, 1*9=9}.....>.....9.

{2*5=10, 5*2=10, 1*10=10, 10*1=10}.....>.....10.

{6*2=12, 2*6=12, 12*1=12, 1*12=12}.....>.....12.

All this no, have factors including factor of itself. Factor of it self i.e. [Example: 1*2, 2*1 ]. But only 11 in the option which has factors for itself we can't get 11 by multiplying with other no. s.

Its factor is {1*11, 11*1}.....>.....11.

This is the factors of 11. Now I hope Lavkush you may got atleast some idea why only 11 why not 9.