MCQ
A random variable $X$ has the following probability distribution:
X01234567
P(X)0P2P2P3P$\mathrm{P}^2$$2 \mathrm{P}^2$$7 \mathrm{P}^2+\mathrm{P}$

The value of P is
  • A
    -1
  • $\frac{1}{10}$
  • C
    $-\frac{1}{10}$
  • D
    1

Answer

Correct option: B.
$\frac{1}{10}$
(B)
$ \text {Since, } \sum_{x=0}^7 \mathrm{P}(\mathrm{X}=x)=1$
$\begin{aligned} & \therefore 0+\mathrm{P}+2 \mathrm{P}+2 \mathrm{P}+3 \mathrm{P}+\mathrm{P}^2+2 \mathrm{P}^2+7 \mathrm{P}^2+\mathrm{P}=1 \\ & \therefore 10 \mathrm{P}^2+9 \mathrm{P}-1=0 \\ & \therefore(\mathrm{P}+1)(10 \mathrm{P}-1)=0 \\ & \therefore \mathrm{P}=\frac{1}{10} \ldots[\because \mathrm{P} \geq 0, \mathrm{P}+1 \neq 0]\end{aligned}$

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