Let P1, P2, ..., P5 be five points, no three of which are collinear. How many lines contain two of these five points? How I thought about solving this was by way of combinations. C5,2= (5*4*3*2)/2 = 60. So there would be 60 lines that contain 2 of the 5 points. Is this a good way to approach this problem or is there a better way? Thank you for your help!