A rifleman is firing at a distant target and has only 10% chance of hitting it, and then which of the following is / are correct?

The minimum number of rounds required in order to have more than 50% chance to hit the target atleast once is

$\mathrm{p}=\frac{1}{10},\mathrm{q}=\frac{9}{10}\Rightarrow 1-{\mathrm{q}}^{\mathrm{n}}>\frac{1}{2}\Rightarrow {\mathrm{q}}^{\mathrm{n}}>\frac{1}{2}$

$\Rightarrow {\left(\frac{9}{10}\right)}^{\mathrm{n}}<\frac{1}{2}\text{ then least }\mathrm{n}=7$

When two attempts are made, the probability that both are failures is $\frac{9}{10}\frac{9}{10}=\frac{81}{100}$

$\mathrm{When} \mathrm{two} \mathrm{attempts} \mathrm{are} \mathrm{made}, \mathrm{the} \mathrm{probability} \mathrm{of} \mathrm{hitting} \mathrm{the} \mathrm{target} \mathrm{at} \mathrm{least} \mathrm{once} \mathrm{is}\Rightarrow 1-\frac{9}{10}\frac{9}{10}=\frac{19}{100}$

$\mathrm{When} \mathrm{two} \mathrm{attempts} \mathrm{are} \mathrm{made}, \mathrm{the} \mathrm{probability} \mathrm{to} \mathrm{hit} \mathrm{the} \mathrm{target} \mathrm{exactly} \mathrm{one} \mathrm{time} \mathrm{is} \Rightarrow \frac{1}{10}\times \frac{9}{10}+\frac{9}{10}\times \frac{1}{10}=\frac{18}{100}$