Choose 3 cards from a deck, if last two are spades what is the chance of first card being a spade? I'm stuck on this problem, and need some explanation if possible :

From 52 cards we take 1, after that we take 2 more, both of which are spades. What are the odds that first card is also a spade?

In particular, I'm not sure how to set up my Hypotheses/Evidence. I have a feeling that there might be some case branching or something but I'm unsure on how to set up the whole problem.

Hint: This question could be asked in a very strange way that might actually be easier to understand: Knowing that the NEXT TWO cards MUST be spades, what are the odds that this first card is a spade?
I should add that JMoravitz's comment is really excellent.
