How did Douglas Adams choose the Ultimate Question?

Question

What do you get if you multiply six by nine?

"Six by nine. Forty two."
"That's it. That's all there is."
"I always thought something was fundamentally wrong with the universe"
...

Well as most people know, the “answer” to this question (in the Hitchhikers universe) is 42.

When Douglas Adams was asked whether he invented this question because six times nine is actually 54, which is 42 when written in base thirteen, he replied:

"I may be a sorry case, but I don't write jokes in base 13."

Then what was it based in?

As seen in this answer, Doug Adams chose 42 (the answer) randomly:

The answer to this is very simple. It was a joke. It had to be a number, an ordinary, smallish number, and I chose that one. Binary representations, base thirteen, Tibetan monks are all complete nonsense. I sat at my desk, stared into the garden and thought '42 will do'. I typed it out. End of story.

but where did he get the question from?

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Update

By question I mean

"What do you get if you multiply six by nine?"

Where did Douglas Adams come up with that question to come out of letters from a Scrabble set? A Scrabble set does not even have all of those letters!

Answer 1

tl;dr: "What do you get if you multiply six by nine?" is not The Ultimate Question

It's established (or at least strongly hinted) that modern humans are descendants of the Golgafrinchans from Ark B.

"Can you imagine what a world would be like descended from those ... cretins we arrived with?" he said.

"Imagine?" said Ford, rising his eyebrows. "We don't have to imagine. We've seen it."

"But ..." Arthur waved his arms about hopelessly.

"We've seen it," said Ford, "there's no escape."

(All of the quotes in this answer are from Chapter 34 of The Restaurant at the End of the Universe.)

So the implication is therefore Arthur and his fellow humans weren't entirely integrated parts of the computer Earth. Shortly before the Scrabble sequence, he and Ford have this conversation:

"Still, something must have come out of it," he said at last, "because Marvin said he could see the Question printed in your brain wave patterns."

"But ..."

"Probably the wrong one, or a distortion of the right one. It might give us a clue though if we could find it. I don't see how we can though."

(Ford speaks first. Emphasis mine.)

So six times nine wasn't necessarily the question, but it might have been close. Or not. Who knows, the Golgafrinchans essentially prevented the Earth from meeting its purpose.

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As for the Scrabble set, note that Arthur had made it himself:

What he was doing was rather curious, and this is what it was: on a wide flat piece of rock he had scratched out the shape of a large square, subdivided into one hundred and sixty-nine smaller squares, thirteen to a side. Furthermore he had collected together a pile of smallish flattish stones and scratched the shape of a letter on to each.

Could you fashion a set of Scrabble letters with the exactly right letter frequencies if you were plopped into the distant past amongst Golgafrinchans and Neanderthals? I doubt it.

However, at another point in the chapter, a Neanderthal spells a flawless "forty two" (this is the inspiration for trying to get The Question with the tiles), despite the set later not containing the letter R. You can probably throw "Douglas Adams ignoring continuity for the sake of a joke" into the mix without surprising anyone.

Answer 2

I think that Douglas Adams just wanted to make the point that

"... something was fundamentally wrong with the universe"

by having a question which gives the wrong answer.

That's all there is to it.

Answer 3

So if I recall correctly, Arthur and Ford are stranded on prehistoric earth with a bunch of original cavemen and the remnants of the Golgafrincham species, indeed the surviviors of a crashed fleet comprising of the entire useless third of the Golgafrincham species (middle managers, telephone sanitizers, etc). It appears that the Golgafrincham are displacing the cavemen who are dying out - which would ruin the computation of the question but Marvin did see a question in Arthur's brainwave pattern.

They realize that the question might still be stored in Arthur's mind and introducing a random element (picking scrabble pieces) might reveal it to them, even if the question is somewhat corrupted by the appearance of the Golgafrincham. This reveals the '6 x 9' question.

Ok, so the 'In-Universe' answer is likely to be either:

1. The appearance of the Golgafrincham on the scene corrupted the computation or
2. This is all an elaborate joke of Deep Thought or
3. Using scrabble pieces is not the right way to get at the question

You say that you cannot spell this question using scrabble pieces, but you must remember that Arthur and Ford were not carrying a scrabble set, so they had to make one themselves in prehistoric earth, and perhaps Arthur can't remember how many different letters a real set has.

Out-of-universe: Well I suspect that just as he grabbed at a suitable answer number, he probably wanted something that was idiotic, useless and just a little bit wrong.

Answer 4

Children often have trouble with 6*9 (often confusing its answer with that for 7*8 or, less frequently in my observation, 6*7 or 8*9). Speculating wildly, I'd suggest that Douglas Adams recalled 6*9 being a question for which an answer was hard to come by--making it a good stand-in for the most difficult such question.