Question Number 180151 by ali009 last updated on 07/Nov/22
$$\left.\mathrm{1}\right){twenty}\:{men}\:{are}\:{invited}\:{for}\:{a}\:{dinner}\:{and}\:{are}\:{to}\: \\ $$$${be}\:{seated}\:{around}\:{a}\:{circular}\:{table}.{how} \\ $$$${many}\:{diffrent}\:{arrangment}\:{are}\:{possible}? \\ $$$$\left.\mathrm{2}\right){with}\:{ten}\:{men}\:{and}\:{ten}\:{women}.\:{how}\:{many} \\ $$$${diffrent}\:{arrangment}\:{are}\:{possible}\:{that} \\ $$$${alternate}\:{men}\:{and}\:{women}? \\ $$$$ \\ $$
Answered by Acem last updated on 08/Nov/22
$$\left.\mathrm{1}\right)\:\mathrm{19}!\: \\ $$$$ \\ $$$$\left.\mathrm{2}\right)\:\mathrm{9}!\:\mathrm{10}!=\:\mathrm{10}\:\mathrm{9}!^{\mathrm{2}} \\ $$