The second number in the given number pairs is obtained by performing certain mathematical operation(s) on the first number. The same operation(s) are followed in all the number pairs except one. Find that odd number pair.

225 : 12

THE LOGIC;

(Square root of each of the 1st term and then answer is added by 3 to get the final answer)

So,

1) 25 : 8,

\(\sqrt {25}\) = 5 +3 =8

2) 169 : 16,

\(\sqrt {169}\) = 13 +3 =16

3) 225 : 12,

\(\sqrt {225}\) = 15 +3 =18 not 12

4) 64 : 11,

\(\sqrt {64}\) = 8 +3 =11

Thus, 225 : 12 is the odd one.