A student is participating in a quiz. One task contains a series of five multiple choice questions. Each of the five multiple choice questions contain four answer choices of which only one is correct. Each of the multiple choice questions have same probability to be chosen by the student who is guessing his answers. What is the probability that the student answers: 1) wrongly to the first question of the series of questions?

2) right to the fourth question of the series of questions? 3) right to the at least four questions in the series of questions?

4) If the quiz contained 22 tasks, what would be the probability, that the student by purely guessing, would get a passing grade (requires at least 50% of the tasks to be correct)?