For a student to qualify, he must pass at least two out of three exams. The probability that he will pass the 1st exam is p. If he fails in one of the exams, then the probability of his passing in the next exam, is p/2 otherwise it remains the same.Find the probability that he will qualify.

A tennis match of best of 5 sets is played by two players A and B. The probability that first set is won by A is 1/2 and if he losed the first, then probability of his winning the next set is 1/4, otherwise it remains same. Find the probability that A wins the match.

The probability of a man hitting a target is (1)/(4) . How many times must he fire so that the probability of his hitting the target at least once is greater than (2)/(3) ?

In a test an examine either guesses or copies or knows the answer to a multiple choice question with four choices. The probability that he makes a guess is 1/3 and the probability that the copies the answer is 1/6. The probability that his answer is correct, given that he copied it, is 1/8. Find the probability that he knew the answer to the question, given that he correctly answered it.

The probability that a student passes a physics test is 2/3 and the that he passes both a physics and English test is 14/25 . The that he passes at least one test is 4/5 . What is the probability that he passes the English test.

The probability that a teacher will give a surprise test during any class meeting is (1)/(5) . If a student is absent on two days, what is the probability that he will miss at least one test ?

In on examination the probability of a student passed in physics is 2/3 , passed in both English,and physics is 14/45, If the probability of passing at least one subject is4/5 , find the probability of passing in English?

A father has 3 children with at least one boy. The probability that he has 2 boys and 1 girl is a. 1//4 b. 1//3 c. 2//3 d. none of these

The probability that a contractor will get a plumbing contract is (2)/(3) and the probability that he will not get an electric contract is (5)/(9) ,if the probability getting of at least one contract is (4)/(5) then what is the probability that he will get both the contract?

A student answers a multiple choice question with 5 alternatives, of which exactly one is correct. The probability that he knows the correct answer is p, 0 lt p lt 1 . If he does not know the correct answer, he randomly ticks one answer. Given that he has answered the question correctly, the probability that he did not tick the answer randomly, is