International Maths Olympiad - 2015

Get ready for some excitement. International Maths Olympiad of this year was held in Chiang Mai, Thailand. You can download the problems from here, but the solutions are not posted yet. Check how many you can solve before they show up online.

This year, US team became the winner after a long hiatus of 21 years. Please note that IMO is held as an individual contest, whereas the team results are based on adding up the scores of six individual contestants from each national team. Here are the top 10 countries for this year.

United States of America

People’s Republic of China

Republic of Korea

Democratic People’s Republic of Korea

Vietnam

Australia

Islamic Republic of Iran

Russian Federation

Canada

Singapore

In other years, the top place is held by China, but they missed that spot this time. I was doing some analysis of scores to find where USA and China differed. Interestingly, very few members of the Chinese team solved Problem 3, but did unusually well with the most difficult problem (Problem 6). Members of Russia, which is usually another top country, stumbled with Problem 5. I spent couple of hours solving Problem 5 and it appears fairly easy to me. Someone please send me the solutions of other five to save me from spoiling the rest of the week.

The real champion of this IMO is Canadian Zhuo Qun (Alex) Song, who got a perfect score. Here are his record from the last six contests.