7

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It is possible that 25 is the correct answer since I guessed (educated guess) that and got a predication of 170 IQ (obviously not accurate)

I saw that

63 + 25 = 88 and

16 + 9 = 25

but then that breaks apart the lower you go.

Any ideas?

I saw that nine was repeated so maybe 25 would also be repeated?

nullUser
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Ghozt12
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    If you don't know then "I don't know" is definitely a correct answer, don't you think? – barak manos Feb 11 '15 at 12:58
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    @barakmanos: it's true, but an IQ test doesn't necessary consider not knowing to be indicative of high IQ, and therefore might not award any points for it. All depends whether the question is one to which a high-IQ person will tend to know the answer, or tend to not know ;-) – Steve Jessop Feb 11 '15 at 13:59

1 Answers1

13

You have to sum the digits

$8+8+6+3=25$

$2+5+9=16$

and go on.

So $x=1+3+4+9=17$

Skills
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    thanks, it seems so simple – Ghozt12 Feb 11 '15 at 13:05
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    By the way, this is not really a "math" question... – Martigan Feb 11 '15 at 13:56
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    @Martigan: No, but it raises one. OP's pattern ("$88 - 63 = 25$" and "$25 - 9 = 16$") breaks after two steps. Is there a puzzle where this "wrong" pattern continues? One can easily give the condition for the difference of two numbers to equal the sum of their digits. How long can one make a CHAIN of numbers for which both patterns hold? That is, writing $\sigma(a,b)$ for the sum of the digits of $a$ and $b$, we select $a_0$ & as many $b_i$ as possible such that $$a_{i+1} = |a_i-b_i| = \sigma(a,b)$$ How far can we go? Trivially, chains with $(a_i,b_i)\in{(0,0),(1,0),(0,1)}$ are unending. – Blue Feb 11 '15 at 20:07