Question on total probability formula

Hi, my question is:

Two different squares are selected at random on an 8 x 8 chessboard. What is the probability that they share a common boundary (i.e. that htey have an edge in common, not just a single corner)?

For this question, it says I'm supposed to use the total probability formula. Any help would be greatly appreciated :)

Re: Question on total probability formula

Hey sakuraxkisu.

I'm not familiar with that term, but you could point out what the total probability formula is in your book/lecturer/whatever?

Re: Question on total probability formula

Re: Question on total probability formula

In my lecture notes, it says that the formula is:

Assuming that form a partition of the sample space and that form a partition of A.

I got the same answer as you Soroban, although my method was slightly different. I think what confused me most was how this formula could be used in the question. Thank you anyway though :)