Tanyakhovanova - blog.tanyakhovanova.com - Tanya Khovanova's Math Blog
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Parallel Weighings Solution 6 Aug 2013 | 05:38 pm
I recently posted the following coin weighing puzzle invented by Konstantin Knop: We have N indistinguishable coins. One of them is fake and it is not known whether it is heavier or lighter than all ...
Ode to My Digital Scale 29 Jul 2013 | 08:19 pm
I valued my previous analog scale: I brought it from Europe and it showed my weight in kilograms. I don’t remember why, a year ago, I decided to buy a digital scale: after all, my old scale is still ...
Discussing a Problem from the Moscow Olympiad 28 Jul 2013 | 06:09 pm
I recently posted the following problem from the Moscow Olympiad: There were n people at a meeting. It appears that any two people at the meeting shared exactly two common acquaintances. Prove that ...
Next Tanya Khovanova 13 Jul 2013 | 07:31 pm
Many years ago at Gelfand’s seminar in Moscow, USSR, someone pointed out a young girl and told me: “This is Natalia Grinberg. In her year in the math Olympiads, she was the best in the country. She is...
Missing Coin 12 Jul 2013 | 08:15 pm
I recently published the following coin puzzle: There are four silver coins marked 1, 2, 3, and 5. They are supposed to weigh the number of grams that is written on them. One of the coins is fake and...
Fraternal Birth Order and Fecundity 28 Jun 2013 | 12:24 am
Two interesting research results about male homosexuality are intertwined. The first one shows that the probability of homosexuality in a man increases with the number of older brothers. That is, if a...
My New Favorite Hat Puzzle 20 Jun 2013 | 06:55 pm
My new favorite hat puzzle was invented by Konstantin Knop and Alexander Shapovalov. It appeared (in a different wording) in March 2013 at the Tournament of the Towns: A sultan decides to give 100 of ...
Samples from My AMSA Homework 6 Jun 2013 | 10:31 pm
I particularly like these two problems that I gave my AMSA students for homework: Athos, Porthos, and Aramis were rewarded with six coins: three gold and three silver. Each got two coins. Athos doesn’...
Parallel Weighings 31 May 2013 | 09:55 pm
We’ve all been hearing about parallel computing, and now it has turned up in a coin-weighing puzzle invented by Konstantin Knop. “We have N indistinguishable coins. One of them is fake and it is not k...
Was I Dead? 31 May 2013 | 09:45 pm
Once when I was working at Telcordia, I received a phone call from my doctor’s office. Here is how it went: — Are you Tanya Khovanova? — Yes. — You should come here immediately and redo your blood tes...
