Question

If five distinct lines lie in a plane, then at most how many distinct points can lie on two or more of these lines?

6
7
8
9
10.

Answer 1

Each line can only cut 4 other lines.
For 5 lines, there will be a maximum of 5*4/2 = 10 intersections. The product has to be divided by two because each intersection had been counted twice, once for each line.