## Matrix with integer sums

Posted on: March 11th, 2013 by
2

Suppose M is a matrix with real entries. Suppose that each of it's rows sum to an integer, and so does each column. Can you always find a matrix $\tilde{M}$ with integer entries that has the same sum along each row and column as M? --Via Kartik Venkat.

## Largest network of cities

Posted on: March 10th, 2013 by
Suppose that there are n cities. Suppose that between any 2 cities, there exists a road with probability c/n. Thus each city is on an average connected to c other cities (for large n). This road network forms a random graph. A connected component of this city network is a set of cities such that one can travel from one city in the set to Continue reading the story "Largest network of cities"

Posted on: March 9th, 2013 by
Why did the chicken cross the road? Watch this viral video for answer:

## Black and white socks

Posted on: March 8th, 2013 by
3

You have 12 black socks and 12 white socks mixed up in a drawer. You're up very early and it's too dark to tell them apart. What's the smallest number of socks you need to take out (blindly) to be sure of having a matching pair? via Brain Teasers

## Special sequence

Posted on: March 8th, 2013 by
What is special about the following sequence of numbers? 8 5 4 9 1 7 6 10 3 2 0 via Brain Teasers