This is going to be either extremely easy or extremely difficult ..
I would rather say I am confused

If you are picking two cards in sequence from a pack of 52 cards. what is the probability that the second card you picked is a spade ?

Before the first card is picked there are 52 cards out of which 13 is spade. so probability of picking a spade is 13/52 = 1/4.
Easy.. now..


I haven't seen the picked card. It can be a spade or something.
Now I pick the second card from the remaing 51 cards.

The number of spades in that 51 may be either 13 or 12 depending on whether my first card was a spade or not.

So the propbability that this second card is a spade can be

13/51 or 12/51 which is ambiguous.

Knowing the probability of picking a spade the first time to be 1/4
how can i remove this ambiguity ??