Of the 25 questions in a unit, a student has worked out only 20. In a sessional test of that unit, two questions were asked by the teacher. The probability that the student can solve both the questions correctly, is
Let A ={1, 3,5,7, 9} and B ={2, 4,6, 8}. An element (a, b) of their cartesian product A x B is chosen at random. The probability that a + b =9, is
Dialling a telephone number, a man forgot the last two digits and remembering only that they are different, dialled them at random. The probability of the number being dialled correctly is
A speaks truth in 60% cases and B speaks truth in 70% cases. The probability that they will say the same thing while describing a single event is
A three digit number, which is multiple of 11, is chosen at random. The probability that the number so chosen is also a multiple of 9 is equal to
A fair die is thrown until a score of less than five points is obtained. The probability of obtaining less than three points on the last throw is
Seven digits from the digits 1, 2, 3, 4, 5, 6, 7, 8, 9 are written in a random order. The probability that this seven digit number is divisible by 9 is
A wire of length 1 is cut into three pieces. What is the probability that the three pieces form a triangle?
Suppose X is a binomial variate B(5, p) and P(X = 2) =P(X = 3), then p is equal to
A bag contains four tickets numbered 00, 01, 10, 11. Four tickets are chosen at random with replacement, the probability that sum of the numbers on the tickets is 23, is