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Author Archives: Alok Goyal
Solution to Puzzle #200: Achieve Your GOAL
Friends, this is a bittersweet moment for me. This is the last post for some time, until I decide to pick up the threads again. Thanks to all of you for making this a wonderful journey for the last 5 … Continue reading
Solution to Puzzle #199: Two-Cube Calendar
This puzzle was originally posted in April 1969 by Martin Gardner, and is a classic even today. Thanks for an overwhelming response to the puzzle and my apologies for the delayed post as I was traveling on work outside the … Continue reading
Puzzle #200: Achieve your GOAL
Its been nearly 5 years since I started posting puzzles, and today is the 200th puzzle. I have thoroughly enjoyed posting puzzles, hearing from so many of you, especially some amazing children over the years. But its time for a … Continue reading
Solution to Puzzle #198: The Neural Network Puzzle
This was a difficult puzzle, even though it was seemingly simple. I did get attempts from a few people, but the only correct answer came from Gaurav S (founder of d8i.ai) – thanks and well done Gaurav! The site from … Continue reading
Puzzle #199: Two-Cube Calendar
Every time you pick up a Martin Gardner book, there is still always a wonderful puzzle that one has not seen. This one is an original Martin Gardner puzzle, i.e. this is his own creation, published in the book The … Continue reading
Solution to Puzzle #197: 10 Friends
This was a relatively simple puzzle, and I got correct answers from Suman Saraf, Mohit Khare, Vishal Poddar and Pratik Poddar – thank you all! The answer is 1024. An easy way to think about this is to create a … Continue reading
Puzzle #198: The Neural Network Puzzle
Thanks to my INSEAD friend Sergio Werner for pointing me to a new source of puzzles and science articles – http://www.quantamagazine.org. I am reproducing a puzzle posted there by Pradeep Mutalik. Neural networks and deep learning are the buzzwords of … Continue reading
Solution to Puzzle #196: Bugs on a Board
Apologies for not posting anything in the last few weeks, was traveling on work or vacation through this period. This was not a very difficult puzzle, but I got correct answers only from the two people who solve every puzzle … Continue reading
Puzzle #197: 10 Friends
This is a very common puzzle, many variants of which one would have. I still like it as the answer is very elegant, and teaches children a methodology. This one is from Mathematical Circles (Russian Experience) by Dmitri Fomin, Sergey … Continue reading
Solution to Puzzle #195: 1989!
I received many correct answers. These included Suman Saraf, Vishal Poddar and Anand Sanghi. Thank you and well done! This puzzle can be solved using the concept of “invariants” and parity. Note that for any numbers a and b (a … Continue reading
Alok Goyal's Puzzles Page 