Question Number 40283 by scientist last updated on 18/Jul/18
$${There}\:{are}\:{four}\:{ladies}\:{and}\:{four}\:{gentlemen}\:{ready}\:{to}\:{play}\: \\ $$$${tennis}.{if}\:{there}\:{is}\:{only}\:{one}\:{tennis}\:{court}\:{readily} \\ $$$${available}.\:{In}\:{how}\:{many}\:{ways}\:{is}\:{it}\:{possible}\:{to}\:{arrange}\:{for}\:{one}\:{mixed}\:{double}\:{to}\:{be}\:{played} \\ $$$$\left({a}\:{lady}\:{and}\:{gentleman}\right)? \\ $$