Question:
What is the probability that a random bridge hand contains cards of exactly two suits?
My Attempt At A Solution Bridge hands consist of $13$ cards, and a suit contains $52$ cards, so the way to pick a random bridge hand would be $$\frac{{13\choose n}{13 \choose 13-n}}{{52 \choose 13}} $$$$\frac{{26\choose 13}-2}{{52 \choose 13}} $$
We want some number of cards, $n$ of ourAs user @Lord Shark the Unknown hinted: there are $13$$26\choose 13$ ways to bechoose hands of two suits but one suit and the rest $13-n$ to be of another suitthose suits is only say hearts, and this is out of the total probability being ${52\choose 13}$another only spades, so we must compensate for those.
Thank you for any corrections/hints.