If n straight lines be drawn in a plane , no two of them being parallel and no three of them being concurrent , how many points of intersection will be there ?

If 20 lines are drawn in a plane such that no two of them are parallel and so three are concurrent,in how many points will they intersect each other?

n lines are drawn in a plane such that no two of them are parallel and no three of them are concurrent.The number of different points at which these lines will cut is a.sum_(k=1)^(n-1)k b.n(n-1) c.n^(2) d.none of these

25 lines are drawn in a plane. Such that no two of them are parallel and no three of them are concurrent. The number of points in which these lines intersect, is: