There are 15 points in a plane, no three of which are collinear. Find the number oif triangles formed by joining them.

There are 15 points in a plane, no three of which are collinear. Find the number of triangles formed by joining them.

There are 21 points in a plane no three of which are collinear. The number of triangles formed by joining them is

There are 10 points in a plane, out of which 5 are collinear. Find the number of straight lines formed by joining them.

There are 10 points in a plane, out of which 6 are collinear. If N is the number of triangles formed by joining these points, then :

There are 10 points in a plane , out of these 6 are collinear. If N is the number of triangles formed by joining these points , then :

There are 21 points in a plane no three of which are collinear . The number of triangle by joining them is