A)The quiz consists of 10 true/false questions. To pass the quiz Judy must answer at least 7 questions correctly. But if Judy guesses on each question, what is the probability that she will pass the quiz?

B)The multiple choice exam has 10 questions each of which has 4 possible answers, only one of which is correct. If Judy, who forgot to study for the exam, guesses on all questions, what is the probability

that she will answer exactly 3 questions correctly?

So I remember the answer for the first part being .172 but need help knowing how to get that answer. iTS followup question only confuses me more.

Help would truly be appreciated...