题目

Tracy: Guess what... I've found a summer job!Mark: That's great! Anything interesting?Tracy: Yes, working at anpark.Mark: Wow, that sounds !Tracy: So, have you found anything?Mark: Nothing yet, but I have a of leads. One is working as an intern for a record company-mostly answering phones. Or I can get a landscaping job again.Tracy: an intern sounds more interesting than landscaping. You'd have better hours, and it's probably not as much work.Mark: Yeah, but a landscaper earns more than an intern. And you get a great tan!已知甲盒内有大小相同的1个红球和3个黑球，乙盒内有大小相同的2个红球和4个黑球．现从甲、乙两个盒内各任取2个球． （Ⅰ）求取出的4个球均为黑球的概率； （Ⅱ）求取出的4个球中恰有1个红球的概率； （Ⅲ）设为取出的4个球中红球的个数，求的分布列和数学期望．