SOLUTION: The math test has 10 multiple choice questions, each with 3 answers. If Betty guesses correctly on the first 3 questions, what is the probability that she will guess correctly o

Algebra ->  Probability-and-statistics -> SOLUTION: The math test has 10 multiple choice questions, each with 3 answers. If Betty guesses correctly on the first 3 questions, what is the probability that she will guess correctly o      Log On


   

Question 719196:
The math test has 10 multiple choice questions, each with 3 answers. If Betty guesses correctly on the first 3 questions, what is the probability that she will guess correctly on the fourth question?
Found 2 solutions by jsmallt9, lynnlo:
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
The fact that Betty guessed correctly on the first 3 questions is irrelevant. For each question on the test, the probability of guessing correctly is 1/3.

Now if the question was "What is the probability of Betty guessing all of the first 4 questions correctly?" Then the answer would be %281%2F3%29%281%2F3%29%281%2F3%29%281%2F3%29+=+1%2F81

The difference between the two is that in the problem as given to you, the first three questions are in the past and we are finding the probability of the next question. In the other question, none of the 4 questions have been answered yet. That problem is asking about a sequence of 4 questions, none of which have happened yet.

Answer by lynnlo(4176) About Me  (Show Source):
You can put this solution on YOUR website!
this is an independent problem 1/10