The 18-year-old German contestant Lisa Sauermann won the International Mathematical Olympiad (IMO) 2011 with a perfect score of 42 points, announced the IMO 2011 organization board on Friday. This is her 4th golden medal in IMO in total, which made her the best participant in the history of the IMO. Jeck Lim from Singapore came second with 40 points. Lin Chen from China came third with 38 points. The most successful teams were from China, the United States and Singapore. The IMO is the largest science Olympiad in the world. The student competitor writes two contest papers on consecutive days, with three problems on each day. Every question is worth 7 points, in total 42 points. This year, the contest took place in the Netherlands for the first time. 564 students from 101 countries and regions took part.