answer all questions with explanation

You work in admissions and decide to accept 18,184 potential students for next years' class. Past experience has found that a student has a 0.71 chance of enrolling at your school next year. Assume each student decides independently of all other students, and each student has the same chance of deciding whether or not to enroll at your school. What is the standard deviation of the number of students you expect to enroll at your school next year? Please round your answer to 2 decimal places