Two straight line intersect at a point O. Points A1,A2,...An are taken on a line and points B1,B2,...Bn are taken on the other line. If the point O is not to be used, then number of triangles that can be drawn using these points as vertices, is

Two straight line intersect at a point O. Points A1,A2,...An are taken

1.	Two straight line intersect at a point O. Points A1,A2,...An are taken on a line and points B1,B2,...Bn are taken on the other line. If the point O is not to be used, then number of triangles that can be drawn using these points as vertices, is
Answer» Two straight line intersect at a point $O .$ Points $A_{1}, A_{2}, . . . A_{n}$ are taken on a line and points $B_{1}, B_{2}, . . . B_{n}$ are taken on the other line. If the point $O$ is not to be used, then number of triangles that can be drawn using these points as vertices, is