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Question Number 119893 by peter frank last updated on 27/Oct/20 | ||
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Answered by Ar Brandon last updated on 27/Oct/20 | ||
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$$\mathrm{P}\left(\mathrm{both}\:\mathrm{black}\right)=\mathrm{P}\left(\mathrm{1}^{\mathrm{st}} \:\mathrm{black}\cap\mathrm{2}^{\mathrm{nd}} \:\mathrm{black}\right) \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:=\frac{\mathrm{26}}{\mathrm{52}}×\frac{\mathrm{25}}{\mathrm{51}} \\ $$$$\mathrm{P}\left(\mathrm{both}\:\mathrm{queen}\right)=\mathrm{P}\left(\mathrm{1}^{\mathrm{st}} \mathrm{queen}\cap\mathrm{2}^{\mathrm{nd}} \mathrm{queen}\right) \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:=\frac{\mathrm{4}}{\mathrm{52}}×\frac{\mathrm{3}}{\mathrm{51}} \\ $$$$\mathrm{P}=\frac{\mathrm{26}}{\mathrm{52}}×\frac{\mathrm{25}}{\mathrm{51}}+\frac{\mathrm{4}}{\mathrm{52}}×\frac{\mathrm{3}}{\mathrm{51}}=\frac{\mathrm{662}}{\mathrm{2652}}=\frac{\mathrm{331}}{\mathrm{1326}} \\ $$ | ||
Answered by Ar Brandon last updated on 27/Oct/20 | ||
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$$\frac{\overset{\mathrm{26}} {\:}\mathrm{C}_{\mathrm{2}} }{\overset{\mathrm{52}} {\:}\mathrm{C}_{\mathrm{2}} }+\frac{\overset{\mathrm{4}} {\:}\mathrm{C}_{\mathrm{2}} }{\overset{\mathrm{52}} {\:}\mathrm{C}_{\mathrm{2}} }=\frac{\mathrm{331}}{\mathrm{1326}} \\ $$ | ||
Commented by peter frank last updated on 28/Oct/20 | ||
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$$\mathrm{thank}\:\mathrm{you} \\ $$ | ||