As I mentioned, there are many ways to solve these problems; some involve circles, some don't. Actually, it is not so much a matter of solving as of...
the number of planes is large, we may need to develop a formula to figure out the duplicated lines. In that case, more than three planes can share a...
Ah ok. Well you've already managed to formulate a completely different problem that is mathematically-equivalent to yours, so I would say that you're...
You say that you "figured out two of the probabilities", but that you are "having trouble with the third one" and weren't "able to answer the second...
The probability that event A but neither event B nor event C has occurred is indeed the sum of the probabilities that 1 or 2 has occurred. This does...