Assuming this is a serious question. The answer is basically "for no particular reason." My memory is not what it once was --- now there's a scary thought!! but --- This whole 75 word contest started when it was suggested by the mods (the suggestion had been made in the inner sanctum of mod workroom before and was dismissed but this time it was different.) It was either
@The Judge or
@Teresa Edgerton --- I want to say T.E. had a previous experience when a writing teacher had assigned students to write some 75 word stories and most of them just couldn't do it. So she wondered if maybe the Chrons community would take up the challenge more than her fellow students had. The first contest it was hoped that maybe we would get at least some entries. I remember a comment thinking that 24 would be a roaring success. We got 42 (of course we all realize that the answer to the universe is 42) and it's been a staple ever since. The limiting factor of 75 words was the reason for the 300 word contest later. The 100 Word challenge came about to focus attention only on the story rather than the author.(❁´◡`❁)