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 lest once is greater than 2/3?

The probability that a teacher will give a surprise test during any class is 1/5. If a student is absent on two day what is the probability that he will miss atleast one test.

Probability that A will pass the exam is (1)/(4) , B will pass the exam is (2)/(5) and C will pass the exam is (2)/(3) . The probability that exactly one of them will pass th exam is

In a school 25% students are failed in Mathematics, 15% in Physics and 5% students fail in both Mathematics and Physics. A student is selected at random. (i) If he is fail in Physics, find the probability that he is fail in Mathematics. (ii) If he is fail in Mathematics, find the probability that he in fail in Physics. (iii) Find the probability that he is fail either in Mathematics or in Physics.

The probability of a man hitting a target is 1/2. How many times must he fire so that the probability of hitting the target at least once is more than 90 %dot

Two students Anil and Ashima appeared in an examination. The probability that Anil will qualify the examination is 0.05 and that Ashima will qualify the examination is 0.10. The probability that both will qualify the examination is 0.02. Find the probability that: Both Anil an Ashima will not qualify the exam.

If a person visits his dentist, suppose the probability that he will have his teeth cleaned is 0.48, the probability that he will have cavity filled is 0.25, probability that he will have a tooth extracted is 0.20, the probability that he will have teeth cleaned and cavity filled is 0.09, the probability that he will have his teeth cleaned and a tooth extracted is 0.12, the probability that he will have as cavity filled and tooth extracted is 0.07, and the probability that he will have his teeth cleaned, cavity filled , and tooth extracted s 0.03. What is the probability that a person visiting his dentist will have at least one of these things done to him?

In an entrance test that is graded on the basis of two examinations, the probability of a randomly chosen student passing the first examination is 0.8 and the probability of passing the second examination is 0.7. The probability of passing at least one of them is 0.95. What is the probability of passing both?

In a test an examinee either guesses, copies or knows the answer to multiple choice question with five choices. The probability that he makes a guess is 1/4 and probability that he copies the answer is 1/8 . The probability that his answer is correct given that he copies is 1/10 . Find the probability that he knows the answer to the question given that he correctly answered it: