Tag Archives: probability puzzles

Puzzle #189: Blue Eyed Sisters

Posted on July 30, 2017 by Alok Goyal

A very interesting two minute puzzle from Martin Gardner’s The Colossal Book of Short Puzzles and Problems. Please do share this with your children as well. If you happen to meet two of the Jones sisters (this assumes that the … Continue reading →

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Solution to Puzzle #174: Happy Birthday!

Posted on April 16, 2017 by Alok Goyal

This puzzle was not an easy one, and one of the ways to make it easier was to solve it for a smaller number of candles and then try to solve for larger number of candles. There is a whole … Continue reading →

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Puzzle #174: Happy Birthday!

Posted on March 12, 2017 by Alok Goyal

This is a very nice puzzle from fivethirtyeight.com (thanks to Suman Saraf for pointing this site to me). It’s your 30th birthday, and your friends got you a cake with 30 lit candles. You try to blow them out, but … Continue reading →

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Puzzle #168: Who Gets the Easter Eggs?

Posted on January 29, 2017 by Alok Goyal

This is a delightful and a very counterintuitive puzzle, again from the NSA collection. Original puzzle has been written by Tim C., an Applied Research Mathematician at NSA. Alice has a dozen cartons, arranged in a 3×4 grid, which for … Continue reading →

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Solution to Puzzle #161: Lost Car Key Puzzle

Posted on December 11, 2016 by Alok Goyal

Apologies for not posting the answer last weekend, I was traveling again 🙂 I guess conditional probability puzzles are not the most popular, I got correct answers only from Suman Saraf and Pratik Poddar, even though I thought that the … Continue reading →

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Puzzle #161: Lost Car Key Puzzle

Posted on November 20, 2016 by Alok Goyal

This is a very nice probability puzzle, variations of which we have done in the past. This one is contributed by Suman Saraf – Thanks Suman! I drive to work, and put my car keys in my pocket. Whenever I … Continue reading →

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Solution to Puzzle #149: The Funny Plane Seating

Posted on August 28, 2016 by Alok Goyal

Apologies for not posting the answer earlier – I was traveling last weekend. This was a difficult problem on a relative scale, and I therefore received the correct from all the die hard puzzle solvers in addition to one my … Continue reading →

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Solution to Puzzle #148: The First Black Ace

Posted on August 14, 2016 by Alok Goyal

This was a bit of a  counterintuitive puzzle – four people sent the correct answers – Suman Saraf, Pratik Poddar, Abhinav Jain and Karan Sharma – well done! The answer is the first card. It is a bit difficult to imagine … Continue reading →

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Puzzle #149: The Funny Plane Seating

Posted on August 8, 2016 by Alok Goyal

A very catchy puzzle contributed by my friend and entrepreneur, Pallav Pandey – thanks Pallav! Imagine there are a 100 people in line to board a plane that seats 100. The first person in line realizes he lost his boarding … Continue reading →

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Puzzle #148: The First Black Ace

Posted on July 30, 2016 by Alok Goyal

Yet another wonderful puzzle from Martin Gardner’s book “The Colossal Book of Short Problems and Puzzles”. This one is a probability puzzle, and something you should try with your children. A deck of 52 playing cards is shuffled and placed facedown … Continue reading →

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