ABCDE is a regular pentagon with F at its center. How many different triangles can be formed by joining 3 of the points A,B,C,D,E and F?
(A) 10
(B) 15
(C) 20
(D) 25
(E) 30
(A) 10
(B) 15
(C) 20
(D) 25
(E) 30
total 6 points and 3 points needed to make a triangle. so total triangles 6C3.gmatnmein2010 wrote:ABCDE is a regular pentagon with F at its center. How many different triangles can be formed by joining 3 of the points A,B,C,D,E and F?
(A) 10
(B) 15
(C) 20
(D) 25
(E) 30
Any 3 points will make same triangle i.e. ABC, BAC, CAB
so total no of different triangles are: 6C3 / 3 = 20
whats the OA? is this approach correct? i am still a beginner...
