题目来自朋友给的老方模考题
觉得这两题缺乏部分关键字 所以自己在练习的时候觉得很怪....
因为记得在写其他来源的类似题目时 都不会有这种情形
第一题
In a class of 20 students, half of them are boys. A student
commitee consists of 7 students who are selected from the class
and the first 6 students are girls
Quantity A Quatity B
The probability that the seventh
2/7
selected student is girl
这题下意识就想是 (10 - 6) / (20 - 6) = 2/7
但后来发现题目里没有 "Randomly selected" 这个我在其他机率题目中
会发现的关键字...