SOLUTION: How many distinct line segments are formed by connecting 20 collinear points?

Every point from this set of 20 points is connected by the line segments with 19 other points.


So, the number of all possible connections is  20*19 = 380.


Each such connecting segment  is counted twice at this way of counting.


So, we need divide 380 by 2 to get the answer   = 190.


ANSWER.  190 segments.