Most Important Selected Qs for JEE AdvancedMathematicsProbability
Die A has 2 white and 4 red faces whereas dic B has 4 white and 2 red faces. A coin is flipped once. If it shows a head, the game continues by throwing die A , if it shows tail, then die B is to be used. If the probability that die A is used is 32 33 when it is given that red turns up every time in first n throws. Then find the value of n
Correct answer
5
Step-by-step solution
P ( R A )= ( 2 3 )^n, P ( R B )= ( 1 3 )^n , in n throws P(R)= 1 2 ( 2 3 )^n+ 1 2 ( 1 3 )^n , in n throws P ( A R )= P ( R A ) P(A) P(R) = 1 2 ( 2 3 )^n 1 2 ( 2 3 )^n+ 1 2 ( 1 3 )^n = 2^n 2^n+1 = 32 33 n=5