Posted by **HM** on Wednesday, November 9, 2011 at 4:18am.

An unprepared student makes random guesses for the ten true-false questions on a quiz. Find the probability that there is at least one correct answer.

Could some one please help me?

And explain to me how they got the answer?

and is there another way besides the tree method?

- PROBABILITY MATH -
**Reiny**, Wednesday, November 9, 2011 at 8:08am
All we have to exclude is the case when he guessed all of them wrong

that prob would be (1/2)^10 = 1/1024

so the prob of getting at least one correct is 1 - 1/1024 = 1023/1024

- PROBABILITY MATH -
**ebony**, Monday, May 14, 2012 at 12:28am
Take 10/2=5

possibility of 5 right or 5 wrong because there is only two possible outcomes

2/100 = .50 (True and False Outcomes)

There are a total of 10 questions

.50^10 questions = .0009765625 rounded = .0009777

use the complement formula 1-P=

1-.0009777 = .9990223 that there is at least once correct answer

## Answer This Question

## Related Questions

- statistics - An unprepared student makes random guesses for the ten true-false ...
- math - An unprepared student makes random guesses for the ten true or false ...
- STAT - A student takes a ten-question true-false quiz, but did not study and ...
- Statistics - Please help. Find the probability of getting 2 hearts if the cards ...
- Statistics - An unprepared student is about to take his first test of the ...
- Math - A student randomly guesses the answers to a four question true or false ...
- Statistics Algebra 2 - A 10-question multiple choice test has 4 possible ...
- Math - On a true-false test, each question has exactly one correct answer: true...
- Math - A multiple - choice quiz contains 5 questions with 4 choices for each ...
- Statistics - On a very short quiz, there is one multiple choice question with 5 ...

More Related Questions