Explanation:
if I understand you correctly, then we have the 4 described cards. 3 of these 4 cards are face cards (Jack, Queen, King).
a probability is always desired cases over totally possible cases.
so, for the first pull we have a probability of
3/4 = 0.75
we have 4 total possibilities, and 3 of them are the desired outcome.
for the second pull we have then only 3 cards left (we did not replace the first pulled card). and because the first pulled card was in this scenario a face card, 2 out of these 3 cards are face cards.
so, the probability to pull a face card here is
2/3 = 0.66666...
when we combine these 2 events into one connected event (we are creating event 1 AND event 2), we multiply the probabilities, giving us
3/4 × 2/3 = 6/12 = 1/2 = 0.5