MCQ
Two cards are drawn without replacement from a well-shuffled pack. Find the probability that one of them is an ace of heart
- A$\frac{1}{{25}}$
- ✓$\frac{1}{{26}}$
- C$\frac{1}{{52}}$
- DNone of these
$(i)$ When first is an ace of heart and second one is non-ace of heart
$ = \frac{1}{{52}} \times \frac{{51}}{{52}}\, \Rightarrow \frac{1}{{52}}$
$(ii)$ When first is non-ace of heart and second one is an ace of heart
$ = \frac{{51}}{{52}} \times \frac{1}{{51}} = \frac{1}{{52}}$
$\therefore$ Required probability $ = \frac{1}{{52}} + \frac{1}{{52}} = \frac{1}{{26}}.$
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| $\mathrm{x}$ | $-2$ | $-1$ | $3$ | $4$ | $6$ |
| $\mathrm{P}(\mathrm{X}=\mathrm{x})$ | $\frac{1}{5}$ | $\mathrm{a}$ | $\frac{1}{3}$ | $\frac{1}{5}$ | $\mathrm{~b}$ |
If the mean of $X$ is $2.3$ and variance of $X$ is $\sigma^{2}$, then $100 \sigma^{2}$ is equal to :