# Executive Function Workout

Here is new brain teas­er from puz­zle mas­ter Wes Carroll.

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.

30

More brain teas­er games:

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1. Jonathan on June 2, 2007 at 9:59

I got a bit low­er than the solu­tion. I am assum­ing that the rules are meant to not allow end­ing up in anoth­er corner?

2. Foo on June 2, 2007 at 11:06

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)

3. Frank Shearar on June 3, 2007 at 2:03

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?

4. Bill LaLonde on June 3, 2007 at 2:35

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).

5. Caroline on June 3, 2007 at 11:14

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!

6. Wes Carroll on June 5, 2007 at 9:20

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

7. Caroline on June 5, 2007 at 11:00

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! :-)

8. Chad W Smith on October 17, 2007 at 9:22

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?

9. Jesse The Space Cowboy on November 28, 2007 at 1:45

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

10. Caio on November 29, 2007 at 11:20

It took me about 15 secs to find the answer and some 30 secs to check it… But nice puzzle.

11. Alvaro on November 29, 2007 at 11:29

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!

12. kam on January 2, 2008 at 4:43

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.

13. Mark on January 6, 2008 at 8:39

7, 6, 7, 6, 4 = 30

14. Mitch on January 6, 2008 at 5:16

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.

15. Amanda on March 4, 2008 at 3:35

I got 30, start­ing with the 7 in the mid­dle, then down to the 6, then 7,6,4=30

16. Aaron on March 23, 2008 at 10:58

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.

17. SammyP on May 15, 2008 at 6:22

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!

18. anthonette on August 5, 2008 at 9:15

i got 30 ;)

19. fat tt on October 18, 2008 at 9:40

7–6‑7–6‑4

20. Egon_Freeman on November 6, 2008 at 12:38

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. :-)

21. T BIGS on March 22, 2009 at 8:41

U HAVE TO START AT THE CENTER NUMBER GUYS READ THE QUESTION. START AT THE CENTER NUMBER WHICH IS 7

22. Eclipse1601 on May 2, 2009 at 8:57

24

23. hailrasec on October 13, 2009 at 10:04

30

SHARPBRAINS is an independent think-tank and consulting firm providing services at the frontier of applied neuroscience, health, leadership and innovation.
SHARPBRAINS es un think-tank y consultoría independiente proporcionando servicios para la neurociencia aplicada, salud, liderazgo e innovación.