I stumbled over a probability paradox on the internet:
If you choose an answer to this question at random, what is the chance that you will be correct?
A) 25%
B) 50%
C) 60%
D) 25%
Given that "at random" means choosing each option with equal probability, each option had a chance of 25% to be correct. But since there are 2 options with 25% as the solution, we get 50% of being correct. In this case, B) would be correct. But then again, the probability of choosing B) at random would be 25%. And so on.
Does this paradox have a name? Is there something I can read on it?
Actually the answer to your question is not contained in possible answers -$0\%$
If we change an answer C)60% to C)0%, then:
If the right answer is $k\%\not\in \{0\%,25\%,50\%\}$, then the right answer is 0%, then the right answer is 25%, then the right answer is 50%, then the right answer is 25%...
The phrase you are looking for is Antinomy.