Question

An urn contains 5 red and 2 black balls. Two balls are randomly selected. Let X represent the number of black balls. What are the possible values of X? Is X a random variable?

Answer 1

The two balls are selected can be represented as BB, BR, RB, RR, where B represents a black ball and R represents a red ball and X represent the number of black balls.
X(BB) = 2, X (BR) = 1, X(RB) = 1 and X (RR) = 0
Therefore the possible values of are 0,1 and 2,
Thus, Xis a random variable.