There are 20 points in plane no three of which are collinear . The number of strainght lines by joining them is

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

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

There are 10 points in a plane out of which 5 are collinear. The number of straight lines than can be drawn by joining these points will be

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

There are 12 points in a plane of which 5 are collinear . Find the number of straight lines obtained by joining these points in pairs .

There 12 points in a plane of which 5 are collinear . Find the number of straight lines obtained by joining these points in pairs.

There are 10 points in a plane and 4 of them are collinear. The number of straight lines joining any two of them is a. 4 b. 40 c. 38 d. 39