OT Puzzle if you have time

52

Left digit is 5, the next number in sequence Right digit is (3 + (4 + 5)) mod 10 = 2

Thank you,

--
Don Kuenz KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

Nope ?, not 54

Not 52 either ?

It's a(n) = n^2 if n is even, a(n) = n^2 - n + 1 if n is odd if you map

3, 5, 7, 9.. into 5, 6, 7, 8... somehow but how and if that's connected isn't quite clear to me, my guess is 64, though.

58?

Reverse the numbers, then add 4 if the result is even?

it's clearly not linear and all quadratic fits give

42

one such fit is -(a+b)^2-15.5(a+b)-16.5

but seriously it's uderconstrained, as the two variables seem confounded in the samples.

--
  When I tried casting out nines I made a hash of it.

Algebra doesn't help because if the first two numbers are coefficients of x and y then the three equations contradict.

How about

x^2=2^x

Then x=2 obviously, but proving it is another matter.

onsdag den 20. november 2019 kl. 19.14.24 UTC+1 skrev Klaus Kragelund:

It is staring you in the face :-) . . . The first 3 equations was simply wrong, 4+5 is 9 :-)

All such "find the next one in the sequence" problems are unconstrained. With a little imagination a very large numbers of "solutions" can be found.

Even as a kid, it irked me that such sequences in IQ tests had one "true" answer.

that's dumb.

55

Not necessarily.

Douglas Adams' Deep Thought was right: - the answer to the ultimate question is "42" - the ultimate question to which that is the answer is, quite correctly, "what is 6*9?"

Base 13, of course.

A more interesting question to Kraus' original puzzler is "are there infinite or uncountable answers to that question?".

However it could also be interpreted so that the next in sequence is

400 or 160000

Two interleaved series with even lines:

2+3 interpreted as (2*3)^2

So 4+5 could be either (4*5)^2 or (4*5)^4

It gets funny on multiple choice IQ tests when two or more of the 5 answers are valid and you have to guess which one the examiner thinks is the right one. I had a friend at university (brilliant but no common sense) who aimed to always choose the wrong one just to make a point.

--
Regards, 
Martin Brown

Ever seen the multiple choice section on a bar exam? Three good answers and one correct answer

No less dumb than abusing the addition symbol, or equality symbol, to mean whatever operation is intended by the "puzzle". ;-)

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Design 
Website: https://www.seventransistorlabs.com/

So it's a math joke.

Well said. Psychopaths typically proclaim "You have no one but yourself to blame." when they try to rationalize their own bad behavior. This puzzle's the relatively rare case where you indeed have no one but yourself to blame for willfully abusing math symbols.

Thank you,

--
Don Kuenz KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.

It's a good interview question. It lets you know as an interviewee it's OK to just get up and leave and not worry at all about whether you lost out on anything.

It's a very clever-boomer question, like when your cranky granpa "proves" his intellectual superiority to the ignorant kids these days by asking what the capital of Djibouti is then smugly pronouncing "it's Djibouti! the capital of Djibouti, is Djibouti."

/chuckles ahhhh clever boomer. If only being clever provided low-cost, reliable, and empathetic senior-citizen healthcare services...