maybe there is someone here who can answer the following question because
I don not understand the basic behind it.

1. How do I find out which probalitity a single event I'm interested in has (like a flip of a coin) ?

2. If I know the probability of such an event, let's say 50:50 hai is it possible that
a sample of such events (say 20 events) have a different probability, e.g. 60:40.

3. How can a casino make money in the long run, e.g. with a roulette table, if
someone only bets on black or red ?

Since I do not have much statistical background I would appreciate an easy to understand answer.

Thanks !