Question

Let x be a discrete random variable. if pr(x<9) = 1/6, and pr(x>9) = 1/3, then what is pr(x=9)?

Answer 1

Answer: 1/2

Explanation:

The probabilities must add to 1, so:

`P(x < 9) +P(X=9)+P(X > 9)=1\\\\(1)/(6)+P(X=9)+(1)/(3)=1\\\\P(X=9)=\boxed{(1)/(2)}`