Question

A true-false quiz has eighteen questions. A student guesses all the answers.
(a) Find the probability of getting ten correct.
(b) Find the probability of getting at least ten correct.

Answer 1

Well, let's think about this. A true of false means that there are 2 answers, right? So, there's a 50% chance that the student will get it right. If said student guesses for 18 questions, how many will they get right? (*Hint: what is 50% of 18?)

Answer 2

Would that equal to 9 questions correct? @mossyfish

Answer 3

Yup! 50% of 18 is indeed 9.

Now let's check out part b. If there is a 50% chance that the student will get 9 correct, what's the chance that the student will get 10 correct?