A Pack of 52 cards is given

By using the formula of probability, we get,

P (E) = favourable outcomes / total possible outcomes

We know, a card is drawn from a pack of 52 cards, so number of elementary events in the sample space will be,

$n(S)={}^{52}C_1=52$

(i) Let E be the event of drawing a black king

$n(E)={}^2C_1=2$

P (E) = n (E) / n (S)

= 2 / 52

= 1/26

(ii) Let E be the event of drawing a black card or a king

$n(E)={}^{26}C_1+{}^4C_1-{}^2C_1$

[We deduct 2 from the total since there are two black kings that have already been counted, and we don’t want to make the mistake of counting it again.]

P (E) = n (E) / n (S)

= 28 / 52

= 7/13