The results of an examination in two papers A and B for 20 candidates were recorded as follows.8 passed in paper `A, 7` passed in paper B, 8 failed in both the papers A and B. If one is selected at random, the probability that the candidate has failed in A or B is

In an examination, there are 500 students, 150 passed the first paper and 350 passed the second paper. 50 students passed both the papers. Find the probability that a student selected at random has failed in both the papers.

In an examination.30% of students failed in Maths,20% of students failed in Chemistry and 10% of students failed in both Maths & Chemistry.A student is selected at random.Find the probability that (ii) The student has failed in Chemistry

In a town 40% people read a news paper A, 30% people read another news paper B and 20% people read both. A person is chosen at random from the town. The probability that the person chosen read only one paper is

In a hostel, 60% of the students read Hindi news paper, 40% read English news paper and 20% read both Hindi and English news papers. A student is selected at random. Find the probability that she reads neither Hindi nor English news papers.

In an examination.30% of students failed in Maths,20% of students failed in Chemistry and 10% of students failed in both Maths & Chemistry.A student is selected at random.Find the probability that (i) The student has failed in Maths.

A candidate take three tests in succession and the probability of passing the first test is p. The probability of passing ech succeeding test p or p/2 according as he passes or fails in the preceding one. The candidate is selected if he passes at least two tests. The probability that the candidate is selected is