Question Number 195964 by mr W last updated on 14/Aug/23
$${the}\:{family}\:{A}\:{has}\:\mathrm{4}\:{members}\:{and}\:{the} \\ $$$${family}\:{B}\:{has}\:\mathrm{5}\:{members}.\:{there}\:{are}\: \\ $$$$\mathrm{6}\:{personsfrom}\:{other}\:{families}. \\ $$$${in}\:{how}\:{many}\:{ways}\:{can}\:{you}\:{arrange} \\ $$$${these}\:\mathrm{15}\:{persons}\:{on}\:{a}\:{round}\:{table} \\ $$$${such}\:{that}\:{no}\:{member}\:{from}\:{family}\:{A} \\ $$$${no}\:{member}\:{from}\:{family}\:{B}\:{are}\:{next}\: \\ $$$${to}\:{each}\:{other}? \\ $$