Question: You are taking a multiple choice quiz with 7 total questions. Each question has 5 possible answers with one correct answer per question.

a) If you select one choice per question and do not leave any of them unanswered, find the total number of possible ways of answering the quiz.

The way I worked it out is Is this correct

b) If you randomly guess on all the questions and don’t leave any blank, find the probability that you will answer exactly 5 of the 7 question correctly.

(Please show the formula as well as the Probability of 1 in ??????? of answering exactly 5 of the 7 question correctly.)