# Category Riddle of the day

## Zarankiewicz’s Problem

Zarankiewicz’s problem plays an important role in extremal combinatorics. Let’s first learn few things about Kazimierz Zarankiewicz from Wikipedia. Unfortunately, his life had a lot of suffering. He had to live the nightmare of concentration camps during World War II and he was a revolutionary. He was not a guerrilla but continued to teach despite the Nazi […]

## Riddle of the day

Towers of Hanoi Let us start with some geography. Hanoi is the capital of Vietnam. From the temperature table in the Wikipedia article, it appears that the weather is really nice throughout the year. Not for ski lovers definitely. The Towers of Hanoi is a cool puzzle. Despite the fact that it is usually being […]

## Humans and Randomness

To be honest, this is an experiment I had though of as being an interesting one but never went into the trouble of doing. Dan Meyer however made it happen and thanks to him we can see that a human despite its good effort to imitate a coin cannot do that well. Why though? Subconscious? For […]

## Geometric mean

Here is my riddle of the day for you. Explain why the following piece of Matlab code returns the following >>blog1(10,3) x=5.477226, y=5.477226 sqrt(x0y0)=5.477226 Here is the piece of code: %lasting gemsfunction function blog1(x0,y0) x=x0; y=y0; for i = 1 : 100000 tmp=x; x = (x+y)/2; y = 2*tmp*y/(tmp+y); end fprintf(‘x=%f, y=%f\n’,x,y); fprintf(‘sqrt(x0y0)=%f\n’,sqrt(x0*y0)); Also, generalize […]

## Quantifying confusion

When a European goes to USA or when a US citizen goes to Europe, he or she may be confused by the different way a date is written down. Specifically, the day “7th November 2011” is written in USA as 11/7/2011 which is the day of 11th of July in Europe. Well, imagine that you […]