While similar, possible and probable have very different meanings.
If you don’t buy a lottery ticket, it’s not possible to win.
Once you buy a lottery ticket, it’s possible that you will win, but not probable.
If you bought 90% of the number combinations (who would do that?), then there would be a high probability that you would win the lottery. (If you purchased all the number combinations, then you would be absolutely certain that one of your lottery tickets would match the winning lottery numbers, although I don’t know if you could call that winning.)
Like the example of buying a single lottery ticket, many things in life become possible with very little effort. However, it often takes much more effort to change possible into probable.
If something is possible, it could happen. Possibility means that there is hope. This is where most things begin.
If something is probable, it is likely to happen. Things that are probable are often a direct result of hard work.
Photo credit: bionicteaching on Flickr.