If three of the six vertices of a regular hexagon are chosen at random, then the probability that the triangle
formed with these chosen vertices is equilateral is :
Solutions · 1
Official solution
Choosing vertices of a regular hexagon alternate, here A1, A3, A5 or A2, A4, A6 will result in an equilateral triangle.
Hence the required probability = \[{2 \over {{}^6{C_3}}}\] = \[{1 \over {10}}\]