One card is drawn at random from a well shuffled deck of 52 cards. In which of the following cases are the events E and F independent?
(i) E : ‘the card drawn is a spade’
F : ‘the card drawn is an ace’
(ii) E : ‘the card drawn is black’
F : ‘the card drawn is a king’
(iii) E : ‘the card drawn is a king or queen’
F : ‘the card drawn is a queen or jack’.
Given: A deck of 52 cards.
(i) In a deck of 52 cards, 13 cards are spade and 4 cards are ace and only one card is there which is spade and ace both.
Hence, P(E) = The card drawn is a spade =
P(F) = The card drawn is an ace =
P(E ∩ F) = The card drawn is a spade and ace both = ..(1)
And P(E) . P(F)
..(2)
From (1) and (2)
⇒ P (E ∩ F) = P(E) . P(F)
Hence, E and F are independent events.
(ii) In a deck of 52 cards, 26 cards are black and 4 cards are king and only two card are there which are black and king both.
Hence, P(E) = The card drawn is of black =
P(F) = The card drawn is a king =
P(E ∩ F) = The card drawn is a black and king both = ..(1)
And P(E) . P(F)
..(2)
From (1) and (2)
⇒ P (E ∩ F) = P(E) . P(F)
Hence, E and F are independent events.
(iii) In a deck of 52 cards, 4 cards are queen, 4 cards are king and 4 cards are jack.
Hence, P(E) = The card drawn is either king or queen =
P(F) = The card drawn is either queen or jack =
There are 4 cards which are either king or queen and either queen or jack.
P(E ∩ F) = The card drawn is either king or queen and either queen or jack = ..(1)
And P(E) . P(F)
..(2)
From (1) and (2)
⇒ P (E ∩ F) ≠ P(E) . P(F)
Hence, E and F are not independent events.