# Question: 1

An urn contains 5 red and 2 black balls. Two balls are randomly drawn, without replacement. Let X represent the number of black balls drawn. What are the possible values of X ? Is X is random variable ? If yes, find the mean of X.

## Solution:

Let X = represent the number of black balls drawn

Number of red balls = 5

Number of black balls = 2

Possible value of X = 0, 1, 2

Yes X is a random variable

Now,       Table for calculation of mean Mean = ∑P(X)   # Question: 2

`        An urn contains 4 white and 3 red balls. Let X be the number of red balls in random draw of three balls. Find the mean of X.

## Solution:

Let X = The number of red balls in random draw of three balls.

As there are 3 red balls, possible value of X = 0, 1, 2, 3            Probability distribution Mean = ∑P(X)   ### Some other question:

1: In a certain collage, 4% of boys and 1% of girls

2: int root cotx + root tanx dx

3: R= {(a, b): a ≤ b²} is neither reflexive nor symmetric nor transitive 