See en.wikipedia.org/wiki/Sleeping_Beauty_problem for the statement of this problem.
This seems to me to be a simple weighted average problem. Because the total number of days awake varies between 1 (Monday if heads) or 2 (Monday and Tuesday if tails on Monday). The frequency of occurrence (or the weight) that tossed coin on Monday is 1 (=100% for every Monday) and on Tuesday is ½ (=50% for one Tuesday over two in average). Then:
Then, the sleeping beauty’s answer is 50% and is not a paradox at all, isn’t it? The classic misunderstanding is to consider that there are three events (or steps) and think that the answer is one-third. But there are not three steps. This is relative to frequencies. Another view is that obviously:
Finally, and until proven otherwise, each time you wake up, with a balanced coin, there is always as much chance of getting heads as tails, isn’t there? So, the answer is obviously 50%. Is there really still confusion about this?
