There are 16 points in a plane out of which 6 are collinear, then how many lines can be drawn by joining these points
106
105
60
55
Required number of lines
= 16C2−6C2 +1 = 120 -15+1 = 106
There are 20 non-collinear points in a plane. How many (a) straight lines (b) triangles can be drawn by joining these points?