We find the probability of the complement event and subtract from 1.

So we first calculate the probability of having no repetitions:

The number of tags with no repetitions is

26×25×10×9×8

The number of possible tags:

26×26×10×10×10

So the probability is

 =

 =

 =

 =

 =





Now to find the desired probability, we subtract that from 1.



That's the exact fraction answer.  But you wanted the decimal
value 



and you want it rounded to the nearest whole percent. 

So it's 31%.

Edwin