# Tag Archives: Aptitude-Probability

take four arbitrary points on a sphere as the vertices of a tetrahedron. What is the probability that the centre of the sphere will be… Read More
Ram speaks truth in 3/4 of cases and Shyam in 4/5 of cases. In what percent of cases while narrating the same event are they… Read More
A box having 5 black and 3 brown flags. Another box having 4 black and 6 brown flags. If one flag is drawn from each… Read More
A 5 digit number is formed by using digits 1, 2, 3, 4 and 5 with no two digits same. What is the probability that… Read More
A bag contains 21 balls numbered 1 to 21. two balls are drawn one after another without replacement. Find the probability that both balls are… Read More
What is the probability that a number selected from numbers [1,30] is prime number? (A) 1/3 (B) 2/7 (C) 5/9 (D) 5/30 Answer: (A) Explanation:… Read More
An urn contains 12 red and 18 white marbles. Two marbles are drawn without replacement one after another. What is the probability that first is… Read More
4 dices are thrown simultaneously. What is the probability that all the dices show the same number. (A) 1/216 (B) 1/36 (C) 4/216 (D) 4/36… Read More
A box contains 6 black, 5 brown and 2 yellow balls. If 2 balls are selected at random, what is the probability that both are… Read More
A and B appeared for an exam. Let A is selected when even x happens and B is selected if the event y happens. The… Read More
Given a coin which gives HEADS with probability 1/4 and TAILS with 3/4. The coin is tossed k times. What is the probability that we… Read More