00:01
Suppose these are contained hundred coins some of the coin are real and have head on one side and tell one another are fake and have heads on both sides so in part a we have to find assume 99 of the coin are real and one is fake with two heads a coin is chosen at random and flip twice both time it land head up and what is a chance it is fake and in part b the sum number of the coin are fake with two head a coin is chosen at random and flip twice both both time it land head up how many of the hundred coin must be paid to give at least 50 % chance that chosen coin is fake so here it is given that the jar contain total number of coin equals to 100 and the sum of coin are real and have heads on the side and the tail on the other have head on the other side.
01:21
Now let e1b event that chosen coin is real.
01:33
Choosen coin are real.
01:38
And e2b, the event of chosen coin are fake.
01:50
And a is the event that when chosen coin is flipped twice, both time its land head up so in part a it is given that out of hundred ninety nine coin are real and one is fake means 99 coins are real and one coin is fake therefore since out of hundred ninety nine coin are real therefore p e1 equals to 99 by hundred and also out of hundred out of 100 one coin is fake therefore p e2 is equal to 1 by 100 now even occurred that it means chosen coin is real therefore now p a by e1 is equal to 1 by 2 into 1 by 2 which is equals to 1 by 4 and if to e 2 occur that it means chosen coin is fake therefore p a by e2 is equals to 1 into 1 is equals to 1 therefore the required probability required probability is equal to probability that chosen coin is fake coin are fake that when chosen coin twice both time is land up head therefore which is equals to p e2 by a, which is equals to p e2 into p .a by e2, which is whole divided by p .e1 into p .e1, using the bias theorem.
04:43
Now, substituting the value, we get 1 by 100 into 1 divided by 99 by 100 into 1 plus 1 by 100 into 1.
05:02
Therefore, it is equals to 1 by 100 divided by 99 by 100 plus 1 by 100.
05:14
Therefore, it is equals to 1 by 100 by 94 by 400...