A bookshelf has 5 red books, 3 blue books, and 4 green books. If you randomly select a book from the shelf, what is the probability that it is blue?

For a binomial distribution. The number of trials is 5 and P(X=4)=P(X=3), then P(X>2) is

A random variable X has the following Probability Mass Function:

Two numbers are selected randomly from a set S={1,2,3,4,5,6} without replacement one by one. The probability that minimum of the two numbers is less than 4 is :

The probability of a shooter hitting a target is $\frac{3}{4}$. How many minimum numbers of times must he/she fire so that the probability of hitting the target at least once is more than 0.99?