Brain Teaser for the Frontal Lobes: Tipping the Scales

Here is a new brain teas­er from puz­zle mas­ter Wes Carroll.

Tip­ping the Scales

free brain teasers for frontal lobes

The top two scales are in per­fect bal­ance. How many dia­monds will be need­ed to bal­ance the bot­tom set?

This puz­zle works your exec­u­tive func­tions in your frontal lobes by using your pat­tern recog­ni­tion, hypoth­e­sis test­ing, and logic.

Four dia­monds


First add up the num­ber of clubs in the first two scales (5). Then count how many clubs are in the bot­tom scale (5). The do the same with the spades, which gets you 5 and 5. There are 4 dia­monds in the top two bal­anced scales. There­fore, it must take 4 dia­monds to bal­ance the third scale since all the oth­er mea­sure­ments are the same.


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  1. Jonathan on June 16, 2007 at 10:16

    How about if we just add spades to the right?

  2. Caroline on June 17, 2007 at 2:16

    Count­ing the num­ber of spades is part of it, but you have to know the pro­por­tion of spades, clubs, and dia­monds to each oth­er to solve the problem.

  3. Amber on June 17, 2007 at 7:50

    This is easy if you aren’t over­ly smart, you just count the items and add. If you use high­er math­e­mat­ics, it’s prob­a­bly more difficult.

  4. Jonathan on June 17, 2007 at 7:55

    I agree with Amber. If we only add more spades, we’ll need some fractions.

  5. Caroline on June 17, 2007 at 11:43

    Aside from the frac­tions, the ques­tion asks “How many dia­monds will be need­ed to bal­ance the bot­tom set?”. So you have to add dia­monds not spades.

  6. Amber on June 18, 2007 at 9:52

    What you see on the first two bal­ance scales is all you have to deal with, just use ’em all up and you can’t go wrong.

  7. Caroline on June 18, 2007 at 3:28


  8. kevin on July 15, 2007 at 9:43

    a culb is worth 7 points, a spade 3 and a dia­mond 5, now do the math!

  9. david on October 17, 2007 at 2:20

    Need 4 more Diamonds!

    Try to add scale #1 plus scale #2 together…


  10. NIcholas on October 17, 2007 at 2:35

    its 4 dia­monds i belive look at the top one theres 1 dia­mond and 3 spades= 2 clubs so take three spades out of the bot­tom scale and take 2 clubs out and add a dia­mond. now theres 3 clubs and 2 spades on the bot­tom scale now look at the mid­dle scale its 3 dia­mond­sand 2 spades = 3 clubs u already have the beg­gin­ing of that on the bot­tom scale now, just add 3 dia­monds and its bal­anced, so in order to bal­ance the bot­tom scale (with out take­ing any­thing off) you need 4 diamonds

  11. Matty on November 28, 2007 at 10:09

    I used a series of for­mu­las with three vari­ables and came up with 4 dia­monds. How­ev­er, just adding the scales prob­a­bly would have worked hahaha.
    Great work, David.

  12. Mitch on January 4, 2008 at 4:01

    I did the same as david and just added scales 1 and 2. No need for for­mu­las lol. 

    4 dia­monds :)

  13. Lmnop on June 18, 2008 at 4:58

    Dan­git. Again, I went the long way. Oh well, at least I got to prac­tice my alge­bra. Haven’t used that in a while.

  14. Samir on July 19, 2008 at 9:41

    I too used high­er alge­bra to solve the prob­lem. I got the cor­rect answer but it took way too long. I won­der why I did­n’t think of the short method in the beginning.

  15. allstar on December 23, 2008 at 5:29

    4! i did it the long way >

  16. Audrey on January 20, 2009 at 4:11

    4. That was easy… they give you the solu­tion for 3 clubs and for 2 clubs, all you had to do was add. It was even nice enough to give you the right num­ber of spades.

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SHARPBRAINS es un think-tank y consultoría independiente proporcionando servicios para la neurociencia aplicada, salud, liderazgo e innovación.

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