If `n` persons are seated on a round table, what is the probability that two named individuals will be neighbours?

When two coins are tossed, what is the probability that two heads are obtained?

There are eight girls among whom two are sisters, all of them are t sit on a round table. Find the probability that the two sisters do not sit together.

A coin is tossed thrice. What is the probability of getting two consecutive tails ?

A coin is tossed thrice. What is the probability of getting two consecutive tails ?

A basket contains 20 apples and 10 oranges out of which 5 apples and 3 oranges are defective. If a person takes out 2 at random what is the probability that either are apples or both are good ?

A committee of two persons is selected from two men and two women. What is the probability that the committee will have (a) no man? (b) one man? (c) two men?

Two natural numbers x and y are chosen at random. What is the probability that x^(2) + y^(2) is divisible by 5?

Find the number of ways in which six persons can be seated at a round table, so that all shall not have the same neighbours n any two arrangements.