A set A has n elements. A subset P of A is selected at random. Returning the elements of P, the set A is formed again and then a subset Q is selected from it. Find the probability that P and Q have no common element.

A is a set having n elements. A subset P of A is chosen at random. The set A is reconstructed by replacing the elements of A. A subset Q of A is again chosen at random. Find the probability that P and Q have no common elements.

A is a set having n elements. A subset P of A is chosen at random. The set A is reconstructed by replacing the elements of A. A subset Q of A is again chosen at random. Find the probability that P and Q have no common elements.

A is a set containing n elements. A subset P of A is chosen at random. The set A is reconstructed by replacing the elements of P. A subset Q is again chosen at random. The Probability that P and Q have equal number of elements, is

A is a set containing n elements. A subset P of A is chosen at random. The set A is reconstructed by replacing the elements of P. A subset Q is again chosen at random. The Probability that P and Q have equal number of elements, is

A is a set containing n elements. A subset P of A is chosen at random. The set A is reconstructed by replacing the elements of P. A subset Q is again chosen at random. The Probability that P cup Q contain just one element, is

A is a set containing n elements. A subset P of A is chosen at random. The set A is reconstructed by replacing the elements of P. A subset Q is again chosen at random. The Probability that P cap Q contain just one element, is