Probability

One card is drawn at random from a well shuffled deck of $52$ cards. Find the probability of drawing

  1. a jack of spades;
  2. a black queen.


Sample space $= S = 52$ cards

$\therefore \;$ Number of elements in sample space $= n \left(S\right) = 52$

  1. Let $A = $ event of selecting a jack of spades.

    Number of elements in $A = n \left(A\right) = 1$

    $\therefore \;$ Probability of event $A = P \left(A\right) = \dfrac{n \left(A\right)}{n \left(S\right)} = \dfrac{1}{52}$


  2. Let $B = $ event of selecting a black queen.

    Number of elements in $B = n \left(B\right) = 2$

    $\therefore \;$ Probability of event $B = P \left(B\right) = \dfrac{n \left(B\right)}{n \left(S\right)} = \dfrac{2}{52} = \dfrac{1}{26}$