I do not know how to approach this coin problem, where to start? When you throw a coin, you can either win $10$ dollars if heads or lose $5$ dollars if tails. After $100$ throws, you win $895$ dollars. Is this a fair coin? What probabilities can you associate with each side of the coin?
Can you please explain how to approach such questions, how to pull out the needed formulas from the wordings? In this case, I honestly do not even remotely know where to start. I was thinking about the expected values. I think this is not a fair coin, but then I can't associate any probabilities to it. 

Here is my answer
I hope it helps
you can also read "a very short introduction to probability " published by oxfor union press , its a nice read.

