Q. 115.0( 1 Vote )

A bag A contains

Answer :

Let E1 be the event of selecting bag A or getting 1or 2 on die.

Let E2 be the event of selecting bag B or getting 3,4,5 or 6 on die.

Let A be the event drawing one red and one black ball.

Now,P(A/ E1) = Probability of drawing a red ball and a black ball

when bag A has been chosen.

P(A/ E1) = 4C1. 6C1/ 10C2 =

P(A/ E2) = Probability of drawing a red ball and a black ball

when bag B has been chosen.

P(A/ E2) = 7C1. 3C1/ 10C2=

Using the law of total probability ,we have

P(A) = P(E1) P(A/ E1)+P(E2) P(A/ E2)


Let p = probability of getting head

and q = probability of getting tail

Let X be the number of heads in the 4 tosses of coin.

X can take values 0,1,2,3 and 4.

Since X is a binomial variate with parameters n=4 , such that

P(X=r) = nCr.pr.qn-r when n=4 , r=0,1,2,3,4

P(X=0) = 4C0.p0.q4-0 = 4C0

P(X=1) = 4C1.p1.q4-1 = 4C1

P(X=2) = 4C2.p2.q4-2 = 4C2

P(X=3) = 4C3.p3.q4-3 = 4C3

P(X=4) = 4C4.p4.q4-4 = 4C4

Thus, the probability distribution of X is given by

Now, mean E(X) =

Variance, Var(X) =

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses

A box has 100 penMathematics - Exemplar

State True or FalMathematics - Exemplar

A random variableMathematics - Board Papers

How many times muMathematics - Board Papers

A card from a pacMathematics - Board Papers

An experiment sucMathematics - Board Papers

A bag A contains Mathematics - Board Papers

On a multiple choMathematics - Board Papers

Mark the correct RD Sharma - Volume 2