From a group of 3 boys and 3 girls, 4 children are to be randomly selected. What is the probability that equal numbers of boys and girls will be selected?
A.1/10
B.4/9
C.1/2
D.3/5
E.2/3
答案:(B)
請問該如何解??
版主: shpassion, Traver0818
yuying \$m[1]:我也認為是D哩
6人取4人 = C(6,4) =15
equal boys and girls => 各取2人
C(3,2) * C(3,2)= 9
--> 9/15 = 3/5
正在瀏覽這個版面的使用者:沒有註冊會員 和 29 位訪客