Three of the six vertices of a regular hexagon are chosen at random. The probability that the triangle with three vertices is equilateral is:
Answer & explanation
Correct answer: option 3
Total no. of triangles = ${^6C}_3$
Total no. of equilateral Δ's = 2
(ACE, BFD)
Probability = $\frac{2}{20}=\frac{1}{10}$