Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Probability

Question:

If a discrete variable X has the following probability distribution :

X $\frac{2}{3}$ 1 $\frac{4}{3}$
P(X) $c^2$ $c^2$ $c$

then c is :

Options:

$\frac{1}{2}$

$\frac{1}{3}$

$\frac{1}{4}$

$\frac{1}{5}$

Correct Answer:

$\frac{1}{2}$

Explanation:

From the table

$∑p_i=1⇒c^2+c^2+c=1$

so $2c^2+c-1=0$

$2c^2+2c-c-1=0⇒2c(c+1)-1(c+1)=0$

so $c=\frac{1}{2},-1$ (Not possible)

so $c=\frac{1}{2}$