The cards are drawn from a well shuffled deck of 52 cards one after the other without replacement. The probability of first card being a spade and the second a black king is ?
Here, is my approach, Upon first draw we got a black spade king $$P(\text{first card is spade}) = \frac{13}{52}$$ $$ P(\text{second black king}) = \frac{1}{51} $$
Upon first draw we don't get a black spade king $$P(\text{first card is spade}) = \frac{13}{52}$$ $$ P(\text{second black king}) = \frac{2}{51} $$ Now, the total probability, $$P= \frac{13}{52} \frac{1}{51} + \frac{13}{52} \frac{2}{51} = \frac{39}{2652}$$
But the actual answer is $\frac{25}{2652}$