Problem B. 4642. (September 2014)
B. 4642. Given that no three of five points in the plane are collinear, prove that there are at most seven acuteangled triangles among the triangles determined by the five points.
(4 pont)
Deadline expired on 10 October 2014.
Statistics:
172 students sent a solution.  
4 points:  95 students. 
3 points:  24 students. 
2 points:  21 students. 
1 point:  16 students. 
0 point:  16 students. 
