Jun 1, 2007
Executive Function Workout
By: Caroline Latham
Here is new brain teaser from puzzle master Wes Carroll. He found this one in the Mensa publication Number Puzzles for Math Geniuses by Harold Gale.
The Fork in the Road
Question:
Start at the center number and collect another four numbers by following the paths shown (and not going backwards). Add the five numbers together. What is the lowest number you can score?
This puzzle works your executive functions in your frontal lobes by using your planning skills, hypothesis testing, and logic.
Click here to get the Answer.
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[…] Caroline Latham presents Executive Function Workout posted at SharpBrains. […]
[…] SharpBrains Forces the reader to use their Frontal lobe with the Fork in the road. (recreational mathematics) […]
I got a bit lower than the solution. I am assuming that the rules are meant to not allow ending up in another corner?
Er… going from the bottom-left corner to top-right gives 4+6+8+6+4 = 28, lower than the number given. Do you mean start in the CENTER? Then the limit applies. (7+6+7+6+4)
If you’re allowed to revisit nodes (I had assumed that way the case until I read Foo), why not 4+6+4+6+4 = 24?
Yeah, the directions here need to be clarified, because as they stand (as several other commenters have noted), there are solutions lower than that given (that answer depends on whether revisiting numbers is allowed or not, but either way it is lower than the given answer).
Let me check. But yes, following Foo’s plan, and not repeating any numbers, I get 28. Foo’s solution goes from the bottom left 4 to the neighboring 6, up to the 8, right to the 6, and right to the 4. But let me see if I can find anything about not ending up in another corner. Good work all! Obviously your frontal lobes are doing okay! If I can’t find a limit, then Foo’s answer stands!
Well, that’s a disappointing turn of events, isn’t it? Insufficiently clear instructions plus a questionable answer makes for unhappy puzzle-solvers, and rightly so.
The official word, if I may be so bold, is as follows:
* The problem statement includes the phrase “without going backwards.” This is intended to mean “without revisiting nodes.” Thank you, Frank, for the excellent outside-the-box observation that that is not clearly specified in the problem statement.
* The problem statement also says “start at THE CORNER.” Clearly this should either read “start at ANY CORNER” or “start at THE CENTER.” I believe that the second of these corrections is the one the problem’s creator intended. Nonetheless, Foo’s solution of 28 is correct assuming the first correction instead.
My apologies for insufficient proofreading, and apologies on behalf of the book in which this problem appears as credited above. Congratulations to Foo and to all who thought this through more clearly than the so-called “experts.”
I’ll be all the more careful in the future!
Wes
To clarify the problem for future puzzle solvers, I have updated the text to require you to start at the center number and not repeat any numbers.
Thanks for the great brain workout everyone! Nice work!
[…] Kilde: http://www.sharpbrains.com/blog/2007/06/01/executive-function-workout/ […]
It’s 30 — start at the center number — it says that. So, you start at 7. 7–6-7–6-4
that’s 30.
What does it mean that this took me like 30 seconds to figure out? Can I join Mensa now?
For some reason the 7–8-7–6-4 Path jumped out at me as being the possible lowest (32). I was hasty and ignored the 6 to the lower right
It took me about 15 secs to find the answer and some 30 secs to check it… But nice puzzle.
Chad: yes, you should contact Mensa and let them know you solved this in 30 secs
Jesse: good try.
Caio: think of the extra benefits. You were training your impulse control and emotional self-regulation by waiting those extra 30 seconds in peace…
Everyone, glad you enjoy this!
[…] 44. Choose the right Fork in the Road. […]
There is still a bit of ambiguity in the question. My answer was 29 and it’s because the question says ‘collect another four.’ Making it sound like I can choose the numbers I want to pick up as I go along the path not going backwards. So I started at the center picked up the 7, then 6, up to 9 ( didn’t collect this one), then 6, down to 9, then 6 and finally 4. So I only collected 7+6+6+6+4 which is 29.
7, 6, 7, 6, 4 = 30
When i started at the center (as per the instructions) best i could get was 30, 7 + 6 + 7 + 6 + 4. I also did this in about 30seconds. Btw to all the poeple who didnt start at the center, i dont think you’ll be going anywhere near mensa, failure to even comprehend simple instructions…dream on.
I got 30, starting with the 7 in the middle, then down to the 6, then 7,6,4=30
I got 30 as being the lowest, I may be wrong but it wasn’t that hard, I just had to check over to see if I missed any combinations, didn’t take me long though.
As Yogi Berra once said: when you come to the fork in the road…take it!
He’s also credited with saying: no wonder nobody comes here anymore — it’s too crowded!
i got 30
7–6-7–6-4
The solution can be very um, “methodical” ^^
First, observe the corners — that’s where the lowest numbers are, so it’s more than likely to end your travel there.
Then, look at the four squares surrounding the center square — 8 9 7 6. Out of those, only a combination of 7 and 6 looks promising.
From there, the easiest path is down-left, with the extra turn to account for the 5th square.
U HAVE TO START AT THE CENTER NUMBER GUYS READ THE QUESTION. START AT THE CENTER NUMBER WHICH IS 7
24
30