NDA 2016 Mathematics question
Out of 15 points in a plane, n points are in the same straight line. 445 triangles can be formed by joining these points. What is the value of n?
Answer: (C)
Solution
Number of triangles , so , giving .
Out of 15 points in a plane, n points are in the same straight line. 445 triangles can be formed by joining these points. What is the value of n?
Number of triangles , so , giving .