Four number-pairs have been given, out of which three are alike in some manner and one is different. Select the one that is different.
Answer & explanation
Correct answer: option 3
THE LOGIC;
1) 31 - 41,
There is 1 prime number between them.
2) 83 - 97
There is 1 prime number between them.
3) 73 - 79
They are consecutive prime.
4) 61 - 71
There is 1 prime number between them.
Thus, 73 - 79 is the odd one.