In a pack of 52 cards, there are 4 queen cards and 13 heart cards.
Let A denote the event that the card drawn is queen and B denote the event that card drawn is heart.
P(A) = 4/52 and P(B) = 13/52
As there is one card which is both queen and heart (queen of hearts), so P(A and B)= 1/52
Using formula, P(A or B) = P(A) + P(B) – P(A and B)
P(A or B) = 4/52 + 13/52 – 1/52
Probability of a card drawn is either a queen or heart = P(A or B) = 4/13