Question-133293

Question Number 133293 by liberty last updated on 21/Feb/21

Commented by mr W last updated on 21/Feb/21

what is the 3rd category? office related books, literature book, and what else?

$${what}\:{is}\:{the}\:\mathrm{3}{rd}\:{category}? \\ $$$${office}\:{related}\:{books}, \\ $$$${literature}\:{book}, \\ $$$${and}\:{what}\:{else}? \\ $$

Commented by som(math1967) last updated on 21/Feb/21

I think 3rd category means 3rd shelf contains officce related 10 books and10litrature books..

$${I}\:{think}\:\mathrm{3}{rd}\:{category}\:{means} \\ $$$$\mathrm{3}{rd}\:{shelf}\:{contains}\:{officce} \\ $$$${related}\:\mathrm{10}\:{books}\:{and}\mathrm{10}{litrature} \\ $$$${books}.. \\ $$

Answered by som(math1967) last updated on 21/Feb/21

determinant (((shelf),(office work),(literature)),(1,(20),0),(2,(15),5),(3,(10),(10))) ∴Probability selected book belongs to 3rd category =(((1/3)×((10)/(20)))/((1/3)×((20)/(20))+(1/3)×((15)/(20))+(1/3)×((10)/(20)))) =((1/2)/(1+(3/4)+(1/2)))=(1/2)×(4/9)=(2/9) ans

$$\begin{array}{|c|c|c|c|}{{shelf}}&\hline{{office}\:{work}}&\hline{{literature}}\\{\mathrm{1}}&\hline{\mathrm{20}}&\hline{\mathrm{0}}\\{\mathrm{2}}&\hline{\mathrm{15}}&\hline{\mathrm{5}}\\{\mathrm{3}}&\hline{\mathrm{10}}&\hline{\mathrm{10}}\\\hline\end{array} \\ $$$$\therefore{Probability}\:{selected}\:{book} \\ $$$${belongs}\:{to}\:\mathrm{3}{rd}\:{category} \\ $$$$\:=\frac{\frac{\mathrm{1}}{\mathrm{3}}×\frac{\mathrm{10}}{\mathrm{20}}}{\frac{\mathrm{1}}{\mathrm{3}}×\frac{\mathrm{20}}{\mathrm{20}}+\frac{\mathrm{1}}{\mathrm{3}}×\frac{\mathrm{15}}{\mathrm{20}}+\frac{\mathrm{1}}{\mathrm{3}}×\frac{\mathrm{10}}{\mathrm{20}}} \\ $$$$=\frac{\frac{\mathrm{1}}{\mathrm{2}}}{\mathrm{1}+\frac{\mathrm{3}}{\mathrm{4}}+\frac{\mathrm{1}}{\mathrm{2}}}=\frac{\mathrm{1}}{\mathrm{2}}×\frac{\mathrm{4}}{\mathrm{9}}=\frac{\mathrm{2}}{\mathrm{9}}\:{ans} \\ $$$$ \\ $$

Commented by liberty last updated on 21/Feb/21

$$\mathrm{thank}\:\mathrm{you} \\ $$

Commented by physicstutes last updated on 21/Feb/21

Excuse me sir: how is this table drawn in this app.

$$\mathrm{Excuse}\:\mathrm{me}\:\mathrm{sir}:\:\mathrm{how}\:\mathrm{is}\:\mathrm{this}\:\mathrm{table}\:\mathrm{drawn}\:\mathrm{in}\: \\ $$$$\mathrm{this}\:\mathrm{app}. \\ $$

Commented by som(math1967) last updated on 21/Feb/21