00:01
Okay, so for part a, we want to find p, c, w, w.
00:06
So given that each question has 5 possible answers, which are a, b, c, d, e, and only one of them is correct, the probability of guessing a question correctly is 1 over 5, and the probability of guessing a question incorrectly is equal to 4 over 5.
00:36
Now, for p, c, w, w, where c denotes a correct answer and w denotes a wrong answer, the multiplication rule tells us to multiply the probabilities of each independent event, which is p of c, p of w, p of w.
00:59
So this is p of c, and this is p of w, which is equal to 1 over 5 times 4 over 5 times 4 over 5, which is equal to 16 over 25 times 5, which is equal to 125, or this is approximately 12 .8%.
01:38
Now for b, we want to find the different arrangements and their probabilities.
01:51
So, for the different possible arrangements of one correct answer and two wrong answers, we have the following...