Need help finding SD of starting salary.

You have chosen biology as your college major because you would like to be a medical doctor. However, you find that the probability of being accepted to medical school is about 10 percent. If you are accepted to medical school, then your starting salary when you graduate will be $390,000 per year. However, if you are not accepted, then you would choose to work in a zoo, where you will earn $43,000 per year. Without considering the additional years you would spend in school if you study medicine or the time value of money, What is your expected starting salary? Expected starting salary Problem 7.03 a1-a2(a2) What is the standard deviation of that starting salary? Standard deviation