## Facebook IQTest Number Puzzler

### June 18, 2010

Today I got an IQTest puzzle on Facebook that I got wrong. I’ve considered it more and I still can’t see what the answer is – though I can tell you it’s not 22. I’m normally pretty good at this sort of thing but this one has me baffled. Maybe I’m over-thinking it or maybe I’m just getting plain dumber as time goes by…

Here’s the question.

Which number should replace the question mark? 14, 19, 22, 6 or 4?

13 | 8 | 3 | 7 |

4 | 1 | 5 | 1 |

8 | 10 | 9 | 2 |

46 | 32 | 26 | 3 |

14 | ? | 11 | 3 |

Any ideas?

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June 28, 2010 at 08:19

Very interesting puzzle (and nice blog too!). If the numbers in each row are a, b, c, and d, respectively, we have a+b=c*d. For example, 13+8=21=3*7, or 14+?=11*3.

June 28, 2010 at 21:24

Good grief. So obvious. How didn’t I see this!? I’ll go with the getting older and dumber thesis. Thanks Vlad.

January 8, 2012 at 22:32

Another hypothesis is that all the row sums are prime numbers.

(13+8+3+7) = 31

(4+1+5+1) = 11

(8+10+9+2) = 29

(46+32+26+3) = 107

(14+N+11+3) = 28+N

Choose N=14,22,6,4, you get sums 42,50,34,32, none of which are prime, but if you choose N=19, this makes the sum 47, which is prime.

– Jared