Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Determinants

Question:

If the probability distribution of a random variable X is as given below :

X

 -1 

0

1

2

3

 P(X) 

K

 $\frac{1}{5}$ 

 2K 

 $\frac{3}{10}$ 

 K 


Then the value of K is :

Options:

$\frac{3}{8}$

$\frac{1}{4}$

$\frac{5}{8}$

$\frac{1}{8}$

Correct Answer:

$\frac{1}{8}$

Explanation:

X

 -1 

0

1

2

3

 P(X) 

K

 $\frac{1}{5}$ 

 2K 

 $\frac{3}{10}$ 

 K 


we know that $\sum P\left(x_i\right)=1$

$\Rightarrow K+\frac{1}{5}+2 K+\frac{3}{10}+K=1$

So  $4K + \frac{2+3}{10} = 1$

$4K + \frac{5}{10} = 1$

$K = \frac{6}{10}$

$K = \frac{1}{2×4}$

$K = \frac{1}{8}$