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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. Alana says:

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

  6. 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.

  7. Beck says:

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

    V = √2 x √2 x √2

  8. 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!!

  9. Alvaro says:

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

  10. Mitch says:

    Yea i found this one very easy.

  11. fluffychenille says:

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

  12. tayler says:

    i love dr. nasty =)

  13. mathlete says:

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

  14. 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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