Question

If 7 points out of 12 are in the same straight line , what is the number of triangles formed?​

Answer 1

Answer:

9, traingles would be formed

Answer 2

Answer:

185 triangles is the number of triangles formed.

Step-by-step explanation:

As this is from permutations and combinations,

There are 12 total no.of points,so 3 points can be selected from 12 points,we can write it as 12↑C↓3 ways.

Now 7 points are in same straight line hence by joing these points we don't get any triangle,but these are also involved in 12↑C↓3 ways.

Therefore,

12↑C↓3-7↑C↓3=220-35=185 triangles.

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