Question 16
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There are 12 points in a plane, of which exactly 5 lie on one straight line. How many triangles can be formed with these points as vertices?
- A 220
- B 200
- C 210 Correct
- D 165
Correct Answer: Option C
All triples = 12C3 = 220
Collinear triples (no triangle) = 5C3 = 10
220 − 10 = 210
Trap: 220 forgets the collinear points.
Answer: 210
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