There’s no joke; the 4th choice (in addition to 25%, 25%, 50%) is arbitrary; it could be 0%, 100%, or anything other than 25% or 50%. The only purpose it serves is to be a 4th option (thus making the probability of choosing any individual answer 25% when choosing randomly).
The question would work just as well if it had 3 options:
I honestly don’t understand the joke with the 60%. I understand the progression until then.
There’s no joke; the 4th choice (in addition to 25%, 25%, 50%) is arbitrary; it could be 0%, 100%, or anything other than 25% or 50%. The only purpose it serves is to be a 4th option (thus making the probability of choosing any individual answer 25% when choosing randomly).
The question would work just as well if it had 3 options:
1/3, 1/3, 2/3.
What progression?
It’s a little easier to figure out if there is one answer that is clearly and unequivocally wrong.
25/25/50/75 or something just doesn’t have as neat a mapping of numbers into conceptual categories, for some reason, to me