An introductory course in probability in a high school in Vancouver is comprised of 20 students. What is the probability that at least two students have the same birthday? Assume that there are 365 days in a year, and that all birthdays are equally likely.

(When answering the questions, writing down the final answer will not be sufficient to receive full marks. Please show all calculations unless otherwise specified. Also define any events and notation that you use in your solutions.)

An introductory course in probability in a high school in Vancouver is comprised of 20 students. What is the probability that at least two students have the same birthday? Assume that there are 365 days in a year, and that all birthdays are equally likely