A Problem from the Moscow Olympiad
Updated: 2013-05-12 15:45:22
Here is a problem from the 2012 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 all the people have exactly the same number of common acquaintances at this meeting.
Show that n can be greater than 4.
My question is: [...]

Math contests can be a lot of fun. SIAM, the Society for Industrial and Applied Mathematics, puts on a contest every year for teams of high school juniors and seniors to propose a solution to a pressing real world problem. The contest promotes lots of hard work, collaboration, and smart thinking. And, the winners get [...]
"Everything flows. Everything is movement."read more
This podcast is an experimental one in that I didn't script the questions the way I usually do. My guest, Ken Fan, and I both decided in advance that we'd go with the flow. And, in my judgment, this is the best podcast I've done -- it felt very natural. Ken is a great guy [...]