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Brain Teaser: Dr. Nasty’s Giant Cube

Here is another mind-bender cre­ated by Wes Car­roll for the Sharp­Brains readers.

Pre­sent­ing …
Dr. Nasty’s Giant Cube

Dif­fi­culty: HARDER
Type: HYBRID (Logic/Spatial)

The dia­bol­i­cal Dr. Nasty has turned his Growth Ray on a per­fect cube that used to mea­sure one foot on a side. The new larger cube has twice the sur­face area of the orig­i­nal. Find the vol­ume of the larger cube.

cube brain teaser

Click to read Hint #1.

Click to read Hint #2.

Click to read Hint #3.

Click to read Hint #4.

Click to read the Solu­tion and Expla­na­tion.

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16 Responses

  1. Masa says:

    Damn, this is propably the eas­i­est puz­zle you have ever posted here.

  2. Caroline says:

    Masa, I’m glad to hear you’re sharp enough to get this one so quickly! Not every­one else has. We’ll post another one tomor­row — come back and see how you do!

  3. Sandman says:

    I don’t like the expla­na­tion beca­sue it relies on rules of thumb. It’s simlple to go to the fun­da­men­tal equa­tions for SA and V. Each side is 1 X 1. Times 6 sides = 6. Dou­ble that is 12. Solve for side length gives √2. V = side length cubed. 2*√2.

  4. Caroline says:


    Thanks for another, very valid explanation!

  5. r says:


  6. Alana says:

    It is annoy­ing to have to down­load the answers and hints to Word. Can’t you make it part of the website?

  7. Alvaro says:

    Hello Alana, we stopped using this Word sys­tem to dis­play answers, given feed­back like yours. The answers to most teasers are now eas­ier to find. Thanks.

  8. Beck says:

    To use the basic vol­ume equa­tion V = H x L x W,

    V = √2 x √2 x √2

  9. Sheri says:

    I agree with Alana, it is very annoy­ing to down­load the hints and answers and usu­ally I don’t. It would be much bet­ter if you could just click and read!!

  10. Alvaro says:

    Hello Sheri, OK, let us think how to make it eas­ier to check the answer. Thanks for the feedback.

  11. Mitch says:

    Yea i found this one very easy.

  12. fluffychenille says:

    Just cre­ate another linked “web­page” for the answer.…the down­load is annoying.

  13. tayler says:

    i love dr. nasty =)

  14. mathlete says:

    tech­ni­cally you cant dou­ble a ‘per­fect’ cube…the answer is irrational…triple a cube yes , never double…well i think so anyway

  15. R V says:

    The older side is 1 Foot.

    As the new area of one side is now 2 square feet, then one side becomes √2 feet (or 1.414 feet). Now the Vol­ume is:

    √2 x √2 x √2 = 2√2 = 2.828 cubic feet.

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