Question

If 2 cards are drawn from a deck of cards, how do you find P(heart or club)?

Answer 1

The above explains the probability of drawing a heart or club in one draw very well. Now let's move over to P(heart or club) when drawing two cards.

This is a bit more complicated. There are two possibilities:
(1) You've already drawn a 'right' at the first draw `P(1stRight)=1/2`
as explained above

(2) You didn't. `P(1stWrong)=1/2`
Then there are 51 cards left: 26 'rights' and 25 'wrongs'. Probability of getting a 'right' in the second draw `P=26/51` multiply by the first being wrong.
So `P(1st Wrong, 2nd Right)=1/2*26/51=26/102`

You may add the probabilities of cases (1) and (2):
`P(H or C)=51/102+26/102=77/102=0.7549` (two cards)