A quiz for a class consists of 5 questions. The questions are multiple choice with 4 possible answers each. A student randomly guesses on all 5 questions. What is the probability of that student...

A quiz for a class consists of 5 questions. The questions are multiple choice with 4 possible answers each. A student randomly guesses on all 5 questions.

What is the probability of that student getting a passing grade? (60% correct is passing)

What is the probability of that student getting a B or better? (a low B is 80%)

What is the probability of that student failing the quiz?