Aka_dama (igo A to kaku) 5-ko to Shiro_dama (igo S to kaku) 4-ko to Ao_dama (Blue no B wo totte, igo B to kaku) toga haitte-iru hako yori, 3-ko wo at random ni toru toki-ni 3-ko tomo A de-aru Kakuritu wo motomeru Mondai.
Kou yatte toku;-
(A ga 5-ko, S ga 4-ko, B ga 3-ko aru toki at randam ni 3-ko erabu D 3-ko tomo A dearu) ＝（ ―――― D 1-ko-me ga A de aru & 2-ko-me mo A de aru & 3-ko-me mo A dearu ) ＝(5/12)*(4/11)*(3/10) ＝1/22 ---- Answer
