Among the students doing a given course, there are four boys enrolled in the ordinary version of the course, six girls enrolled in the ordinary version of the course,and six boys enrolled in the higher version of the course. How many girls must be enrolled in the higher version of the course if sex and version of the course are to be independent when a student is selected at random?

A plays tennis against B. During a given game, the score reaches deuce. Each player then needs to score two more points than the other to win the game. Assuming that each point is independently won by A with probability p, what is the probability they will have to play a total of 2n points to end the game? What is the probability that A will win the game?

Suppose the random variable X is continuous and has the distribution F(x). Consider another random variable Y de?ned by Y = F(X). Find the distribution of Y .

In a sequence of independent identical trials with two possible outcomes on each trial, success or failure, and with P(success) = p, what is the probability  that exactly x trials will occur before the rth success?