Question

The number of triangles that can be formed by choosing the vertices from a set of 12 points, seven of which lie on the same straight line, is

• A. 185
• B. 175
• C. 115
• D. 105

Answer 1

Answer: (A)

185

Answer 2

Required number of ways = $12C_{3} -^{7} ⥂ C_{3}$ = 220 – 35 = 185.