You need to be sure!
From a regular polygon of 50 - sides , you have to select 3 vertices ( at random) .You selected the triplets \(n \) times .
What is the value of \(n\) to surely say that you have at least a triplet which form obtuse- angled triangle upon joining.
After selecting first triplet, for the second triplet you have to select again from the 50- vertices (not from the left 47 vertices)
No repetition of the same triplet is allowed
You are selecting the vertices with eyes closed. (You can't check , whether the condition is satisfied)
Try my set : Let's play with polygons