3) Guessing on an exam. In a multiple-choice exam, there are 10 questions and 4 choices for each question (a, b, c, and d). Joe has not studied for the exam at all and decides to randomly guess the answers. What is the probability that:
a) The first question they get right is the 7th question?
b) They get all of the questions right?
c) They get at least one question right?