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

Posted in Solution | Tagged , | 1 Comment

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

Posted in Solution | Tagged , | Leave a comment

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

Posted in Puzzles | Tagged , | 6 Comments

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

Posted in Solution | Tagged , , | Leave a comment

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

Posted in Puzzles | Tagged , | 1 Comment

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

Posted in Solution | Tagged , | Leave a comment

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

Posted in Puzzles | Tagged , | Leave a comment

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

Posted in Solution | Tagged , , , | Leave a comment

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

Posted in Puzzles | Tagged , | 3 Comments

Solution to Puzzle #195: 1989!

I received many correct answers. These included ┬áSuman 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

Posted in Solution | Tagged , , | Leave a comment