Category Archives: Puzzles

Fun Math Puzzles – 1

Posted on August 17, 2021 by kevin

My calculator is broken, it only has two working buttons. One of them adds $1$ to the result and the other doubles it. What is the minimum number of presses needed to get to 2021? Click for the solution We … Continue reading →

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Elon Musk’s Interview Question

Posted on July 27, 2021 by kevin

It is known that Telsa/SpaceX CEO Elon Musk would ask a job candidate some brain teaser questions during an interview, such as the following: You’re standing on the surface of the earth. You walk one mile south, one mile west, … Continue reading →

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Cyclic System of Equations

Posted on April 11, 2021 by kevin

Find $abc$. $$ \begin{array}{ll} a+\dfrac{1}{bc} = \dfrac{7}{6}\\ b+\dfrac{1}{ca} = \dfrac{7}{3}\\ c+\dfrac{1}{ab} = \dfrac{7}{2} \end{array} $$ Solution Multiply the first equation by $bc$, the second by $ca$, and the third by $ab$: $$ \begin{array}{ll} abc+1 = \dfrac{7}{6}bc\\ abc+1 = \dfrac{7}{3}ac\\ abc+1 … Continue reading →

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Who is the thief?

Posted on February 3, 2020 by kevin

Four burglary suspects, A, B, C, D were summoned to the court to face the judge. When the judge asked: “Who is the thief?”, each of the suspects answered as following: A: B is the thief.B: C is the thief.C: … Continue reading →

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