-->

Probability

Question
CBSEENMA12035957

Probabilities of solving problem independently by A and B are 12 and 13respectively. If both try to solve the problem independently, find the probability that

(i) the problem is solved

(ii) exactly one of them solves the problem.

Solution

The probability of solving the problem independently by  A  and  B  are given as  12  and   13  respectively.

i.e.  P ( A ) = 12,  P ( B ) = 13. P  A  B  = P  A  . P  B 

[ Since the events corresponding to  A  and  B  are independent ]

= 12 x 13 = 16

( i ) Probability that the problem is solved 

= P  A  B  = P  A  + P  B  - P  A  B = 12 + 13 - 16= 3 + 2 - 16= 46= 23Thus, the probability that hte problem is solved is  23.

( ii ) Probability that exactly one of them solves the problem

= P  A - B  + P  B - A =  P ( A ) - P ( A  B ) +  P ( B ) - P ( A  B )  =  12 - 16  +  13 - 16 = 3 - 1 + 2 - 16= 36= 12Thus, the probability that exactly one of them solves the problem is 12.

Some More Questions From Probability Chapter