Total no. of cards =52 13 cards are diamonds and 4 cards are king. There is only one card which is a king of diamond. ‌∴P‌ (card is diamond) ‌=‌
13
52
,P‌ (card is king) ‌ ‌=‌
4
52
‌P‌ (card is king of diamond) ‌=‌
1
52
‌∴‌‌P‌‌‌ (card is diamond or king) ‌ ‌=‌