There are 12 points in a plane, of which exactly 5 lie on one straight line and no other three are collinear. How many triangles can be formed using these points as vertices?
Correct answer C. 210
Explanation
All triples = 12C3 = 220. The 5 collinear points give 5C3 = 10 triples that form no triangle. Triangles = 220 - 10 = 210.
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