(2) The probability that the leader of a subject is a girl is 0.4, and the probability of all five subjects is (0.4) 5 = 0.0 1024.
(3) Up to 2 digits include 0 digit,/kloc-0 digit and 2 digit.
The probability of 0 bit is (0.6) 5 = 0.07776.
The probability of 1 bit is c (5, 1) * 0.4 * (0.6) 4 = 0.2592.
The probability of two digits is c (5 5,2) * (0.4) 2 * (0.6) 3 = 0.3456.
Where C(5, 1)=5 indicates that two of the five courses are female group leaders, and c (5,2) 2)= 10/0 indicates that two of the five courses are female group leaders.
It adds up to 0.68256.
(4) There are at least three boys and at most two girls, so the answer is the same as (3)