Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Probability

Question:

If the random variable X has the following probability distribution:

x

-1

0

1

2

P(X = x)

k

2k

3k

$\frac{k}{2}$

then P(X ≤ 0) is equal to: 

Options:

$\frac{6}{13}$

$\frac{4}{13}$

$\frac{2}{13}$

$\frac{3}{7}$

Correct Answer:

$\frac{6}{13}$

Explanation:

In the given problem we have 

x

-1

0

1

2

P(X = x)

k

2k

3k

 

k/2

 

We know that the sum of total probability will always equal to one

so, k +2k + 3k + k/2 = 1

⇒ k = 1/3

Now P(X ≤ 0) = P(0) + P(-1)

                     = 2k + k

                     = 3k 

               Since k = 1/13

Hence P(X ≤ 0) = 3/13