FFS. The last sentence is incorrect. They paid $27 for the room (as stated in the previous sentence). The bell boy kept the other two dollars, otherwise they would have paid the corrected $25 rate. There is no paradox.
No. $27 - $2 = $25
Any reference to $30 became totally irrelevant when the price changed and when they each got a dollar back. The $30 became $27 at that point, and then you simply have Bellboystein pocketing the other $2.
We desperately need higher IQ shills. Or I need to smoke a shit ton more weed. Can't decide.