Probablility Problem

[BillP]

I think that we're making this problem harder than it realy is. If we assume that the answer to Daniel's question is "no", the dots on either line cannot occupy the same point, then the answer is:

for line 1, there is a 50% probability that the intersection falls on a dot
for line 2, there is a 25% probability that the intersection falls on a dot

therefore,

for both to occur, the probablility is 50% x 25% (or mathematically)

0.5 x 0.25 = .125, so there is a 12.5% probability (1 in 8) that both lines will be on dots at the intersection.

Or am I wrong?

(don't think so)