SOLUTION: An unprepared student takes a 3-question true/false quiz in which he guesses the answers to all 3 questions. What is the probability he gets all 3 correct?

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Question 1172176: An unprepared student takes a 3-question true/false quiz in which he guesses the answers to all 3 questions. What is the probability he gets all 3 correct?

Found 2 solutions by math_tutor2020, ikleyn:
Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

The probability of getting the correct answer is 1/2 on any given question.

Each question is independent of any other, so we multiply out the fraction (1/2) with itself three times getting (1/2)*(1/2)*(1/2) = (1*1*1)/(2*2*2) = 1/8

Use of a calculator shows
1/8 = 0.125
This converts to 12.5% when moving the decimal point over to the right 2 spots.

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Answer as a fraction = 1/8
Answer as a decimal = 0.125
Answer as a percentage = 12.5%
All values are exact

Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.

In all, there are  2%5E3 = 8  possible different outcomes, combined of possible answers,

and only ONE of them is correct.


So, the probability to get 3 answers correct is  1%2F2%5E3 = 1%2F8.    ANSWER
Solved.