I first heard that story as a room rental to three people who paid $30 (Gee, there's no problem with the dollar sign, must be an 'Anglo' thing) for a night in a hotel, the clerk realized he'd overcharged by $5 and gave it to the bellboy, who on his way up to the room realized the three customers would be grateful to get ANY money so he gave each of 'em $1. That item drove me CRAZY. It percolated through my tiny mind for literally years. I figured it out in an 'AHA' moment during a vacation in London of all places on the top of one of those dear old double decker buses that Flanders and Swann sang about, this one had an open top.

I hear those buses are being or have been done away with, so fear greatly that there will be a reduction in ratiocination at automotive elevations.

Cheerio.

(Now if I could only figure out why mirrors switch left with right, but not top with bottom? Wonder if any of those busses work on our side...)