NCERT Class XII Mathematics Chapter - - Solutions

Question : 15

Total: 101

Consider the experiment of throwing a die, if a multiple of 3 comes up, throw the die again and if any other number comes, toss a coin. Find the conditional probability of the event ‘the coin shows a tail’, given that ‘at least one die shows a 3’.

Solution:

The sample space S is given by

S={

(3,1),(3,2),(3,3),(3,4),(3,5),(3,6)

(6,1),(6,2),(6,3),(6,4),(6,5),(6,6)

(1,H),(1,T),(2,H),(2,T),(4,H),(4,T)

(5,H),(5,T)

}

Let E : ‘the coin shows a tail’ and F : ‘atleast one die shows a 3’
E = {(1, T), (2, T), (4, T), (5, T)} and
F = {(3, 1), (3, 2), (3, 3), (3, 4), (3, 5), (3, 6), (6, 3)} ⇒ E ∩ F = ϕ
∴ P(E) = 4/20, P(F) = 7/20, P(E∩F) = 0/20
Hence, the required probability =P(E|F)=

P(E∩F)

P(F)

=0.

Go to Question:

Prev Question

Next Question