Suppose that the percentage of college students who engage in binge drinking, which is defined as having 5 drinks for male students and four drinks for female students at one "drinking occasion" during the previous two weeks, is approximately 40%. Let X equal the number of students in a random sample of size n=12 who binge drink.

So it asks me to find the mean and the variance and the stan. dev, I'm just not sure where to start.. If I can find the p.m.f I can do the rest but I tried 4/10(40%) and that didnt work out so I need help now