Next number in this sequence

[Winston]

We have a lot of brilliant minds here, that's been demonstrated time and time again.

So I'm sure that someone will be able to solve this little puzzle also. It's one of 78 questions in the Danish Armed Forces' IQ test for prospective recruits. It is rumoured that none of the 2 million men who've taken the test over the past 50 years, have managed to answer every question correctly. But anyway.

What is the next number in this sequence, and why?

572,937 - 84,632 - 4,657 - 624 - 38 - ?

If you want to be a good sport about it, post your answer and explanation in spoiler tags, like this, but with better spelling... [spooiler]bla-bla[/spooiler].

I'll give the answer and explanation at Noon GMT tomorrow.

[Edan]

Spoiler:

I get 1 (10, 100, 1000, etc, would also work, but don't follow the pattern of losing one digit with each number). If you sum up all the digits of each number, you get: 33, 23, 22, 12, 11. The tens and ones decrease every other time, so the next one should be 01.

[alva]

[q]We have a lot of brilliant minds here, ^/q]

Do tell 'cause I've been looking high and low yet found nothing.

[Atahualpa]

Do they use a calculator?

[DeathByTheSword]

Spoiler:

add 572937=33 add 84632=23 add 4657=22 add 624=12 add 38=11 thus
33 23 22 12 11 ... 33-23= 10 23-22= 1 22-12= 10 12-11= 1 11-...=... thus
difference -10 -1 -10 -1 ... most likely will be a -10 differencethus 11-...=10 ...= 11-10 ...=1 ok making a number out of 1 most likely looking at the losing a digit of the other steps this will just be 1

best way of writing this down I believe after the adding of the seperate number is something like this X(n)= X(n-1)+(10/T) where T : X(2n)=10 and T: X(2n+1)=1...you can probably also write is differently and also probably something for the first step (taking apart the number in single digits and counting them)

DBTS

[Provost Harrison]

Well that is plain ridiculous for an exam question...

[Winston]

Originally posted by Provost Harrison
Well that is plain ridiculous for an exam question...

Well you're plain ridiculous for not being able to figure out this is not an exam question.

It's one of 78 questions in an IQ test, used to determine if young men are fit for military service, and if so, I imagine to give a pointer as to what positions they would fit into. If I remember correctly, you have something like 50 minutes for the test.

[Atahualpa]

nvm... I read the spoilers... honestly I'd have put the same number, but just guessing... I just had the feeling it fit

[Thue]

Originally posted by Winston


Well you're plain ridiculous for not being able to figure out this is not an exam question.

It's one of 78 questions in an IQ test, used to determine if young men are fit for military service, and if so, I imagine to give a pointer as to what positions they would fit into. If I remember correctly, you have something like 50 minutes for the test.

I remember that one... I got all the numeric questions but that one correct when I was draftet.

I did get a very satisfactory total score. In fact they tried to get me to sign up as an officer, which I refused.

[Urban Ranger]

Spoiler:

The answer is 1, but the question is stupid

[Ecthy]

I was very close because I had already tried that approach but stopped half the way through because there didn't seem to be a system. Now there's one more proof I give up too early. Just like in real life.

[Winston]

Yes, the answer is 1.

And the explanations posted by Edan and DeathByTheSword are also correct.

First we see that the answer should be single-digit, since the preceeding numbers have 6, 5, 4, 3 and 2 digits respectively.

Then by summing up the digits of the numbers given, and summing up the digits in those results, we get sums of 6, 5, 4, 3 and 2.

So the only single digit number that would fit in the seguence is... 1.

Saw it on a newspaper website here, where the journalist had managed to figure out that the answer was "1", but couldn't explain why. And so he finally got a hold of the military guy in charge of the test, who would only confirm that the answer was correct, but not WHY. (Presumably as not to compromise the actual test question.) So the journalist asked the readers of the paper to mail in if the had the explanation and got 2,000 replies, many of which were right on. But the newspaper guy must be really stupid, since he posed the question as "What's the last number in this sequence: 572,937 - 84,632 - 4,657 - 624 - 38 - ", and so one guy mailed him and said "38, I think".

If anybody has any other puzzles etc., feel free to post them, challenge your fellow posters' intellect a little.

[Provost Harrison]

Here is one I saw in the paper the other day:

Convert the word at the top to the word at the bottom, but only changing one letter at a time:

Poodle
------
------
------
------
------
Canoes

[Colonâ„¢]

Poodle
Coodle
Condle
Candle
Canole
Canols
Canoes

[Provost Harrison]

A lot of those aren't real words!

But you're right, I never said they had to be real words I thought it was stupid...usually they require some amount of skill