Stumped by IQ test: help from uberbrain needed

[marinyork]

[sup]My typing is correct. (Anyway, I think it unlikely that the solution is as complex as cyclic numbers.)
[/sup]

In fairness I have actually seen questions in quizes that refer to cyclic numbers as well as things like the next Mersenne prime in a sequence, perfect numbers and triangular numbers. It's not any harder than them in a way. Strangely enough I had to use the sequence in a course on representation theory.

Problem is if you don't put enough numbers in the sequence, it doesn't narrow it down enough to what people might plausibly expect (still many sequences it could be). As for the claimed sequence, with 23 following 15, that's actually listed on sloane, just it doesn't elaborate a great deal.

 

[asterix]

Since my answer is logical I'd suggest the problem is not nearly as complex as that. If you want to take it further, just forget about the base ten numbering system and think of other numbering systems such as hex (base 16), octal and binary. In this case it is a base 5 system with only 5 symbols: 1 3 5 7 9 so the series would be

1 3 5 7 9 11 13 15 17 19 31 33 35 37 39 51 53 55 57 59 71 73 75 77 79 91 93 95 97 99 111 113 115 117..

Pretty simple.

 

[ohnovino]

Since my answer is logical I'd suggest the problem is not nearly as complex as that. If you want to take it further, just forget about the base ten numbering system and think of other numbering systems such as hex (base 16), octal and binary. In this case it is a base 5 system with only 5 symbols: 1 3 5 7 9 so the series would be

1 3 5 7 9 11 13 15 17 19 31 33 35 37 39 51 53 55 57 59 71 73 75 77 79 91 93 95 97 99 111 113 115 117..

Pretty simple.

Not quite. The second value in the original sequence is "2".

 

[MacB]

Not quite. The second value in the original sequence is "2".

Weak slapdown, Asterix nailed it while everyone else was getting bogged down in the weird and wonderful. I couldn't work it out but, as it was a quiz, was pretty sure that it wasn't Marins answer

 

[spire]

The sequence is:

1, 2, 3, 5, 7, 11, 13, 15,...

With the missing number published as 23.

So unfortunately, asterix hasn't nailed it!

 

[ASC1951]

Pretty simple.

Ahem. There may well be a single answer which the questioner expects, but there is no "correct" answer. If you have the given numbers in any list representing the roots of a polynomial equation, you can continue with whatever numbers you wish and write a formula to generate that sequence.

 

[MacB]

The sequence is:

1, 2, 3, 5, 7, 11, 13, 15,...

With the missing number published as 23.

So unfortunately, asterix hasn't nailed it!

Fair enough, I haven't looked that hard, it's either way beyond my mathematical ability, as in the Marin route, or it's very obvious/silly, but I can't see it. If it's the former then I'm not going to understand it anyway and the latter I'll raise half an amused eyebrow.

 

[asterix]

The sequence is:

1, 2, 3, 5, 7, 11, 13, 15,...

With the missing number published as 23.

So unfortunately, asterix hasn't nailed it!

Oops, my mistake!

I'd suggest if the people on here can't solve this, it's a tough one!

 

[spire]

Oops, my mistake!

I'd suggest if the people on here can't solve this, it's a tough one!

It seems so tough that I think it must be wrong as the other questions were relatively easy!

I've just found this review: http://www.amazon.co.uk/Teach-Yourself-Training-Brain-General/dp/0340965088

It seems others have the same problem.

 

[Ravenbait]

Another of the questions:

Which is the odd word?

Through, thought, thorough, trough, tough, brought?

Through, I'd have said, because it's the only one to use the "oo" vowel sound. There are at least two of the other pronunciations.

Sam

 

[threebikesmcginty]

Through, I'd have said, because it's the only one to use the "oo" vowel sound. There are at least two of the other pronunciations.

Sam

Isn't it the last word as it's the only one that doesn't begin with a 't' - or is that too simple?

 

[Ravenbait]

Isn't it the last word as it's the only one that doesn't begin with a 't' - or is that too simple?

I dunno. I think it's like Have I Got News For You. There is more than one odd one out: the trick is picking the one that the question-setter also picked.

Sam

 

[threebikesmcginty]

There is more than one odd one out: the trick is picking the one that the question-setter also picked.

Ok, maybe it's 'thorough' then, due to the extra syllable!

That's three answers so far, I see what you mean...

 

[byegad]

Primes. Next is 17, 19, 23....

15 divides by 3 and 5 and so is not a prime. 1 is generally not regarded as a prime either. rimes have 2 factors, themselves and 1.

 

[Flying_Monkey]

It should be noted that 'better' IQ tests, if there are such things anyway, will accept any answers that are valid. If they don't, then the tests (or those giving the answers) aren't as clever as they think.