Arithmetic Ability
Permutations and Combinations

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Q.

In a plane 8 points are colliner  out of 12 points, then the number of triangles we get with those 12 points is 

View Answer

Correct choice: C

Explanation:

For a triangle, we need 3 non-collinear points. So with 12 points (when all the 12 are such that any three non-collinear is12C3 . But among them 8 points are collinear. If all these 8 points are different we get 8C3 triangles as they are collinear. In 12C3 triangles, we do not get 8C3 triangles Therefore, The number of triangles we get = 12C3−8C3 = 164
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