# Math

posted by .

10 multiple choice questions each with three possible answers only one of which is correct. A student guesses the answer to every question.

(a)What is the probability that the student will answer the first six questions correctly and the rest incorrectly?
(b)What is the probability that the student will answer the 1st,2nd,4th,6th,7th,and 10th questions correctly and the rest incorrectly?
(c)How many ways can the student get exactly 6 correct answers?
(d)What is the probability that the student answers exactly 6 questions correctly?

Thank you so much for your help...

• Math -

Prb(right) = 1/3, prb(wrong) = 2/3

a) you want
rrrrrrwwww
prb(rrrrrrwwww) = (1/3)^6(2/3)^4
= 16/59049

b) you want rrwrwrrwwr or the same as above

c) now the order does not matter, you want to choose 6 out of 10 which is
C(10,6) = 10!/(6!4!) = 210

d) prb(6 out of 10) = 210/59049 = 70/19683

• Math -

You have a 5-question multiple-choice test. Each question has four choices. You donâ€™t know any of the answers. What is the experimental probability that you will guess exactly three out of five questions correctly?

• Math -

P(3 correct)= (.25)^3 x (.75)^2 combinations; 5C3= 5!/3!2!= 10
answer is 1/64 x 9/16 x 10 = 90/1024

• Math -

I have no idea

• Math -

fake

## Similar Questions

1. ### statistics

A multiple choice test has 20 questions with each having 4 possible answers with one correct. Assume a student randomly guesses the answer to every question. 1) What is the probability of getting exactly 9 correct answers?
2. ### Binomial Distribution

A biology quiz consists of twelve multiple-choice questions. Eight must be answered correctly to receive a passing grade. If each question has five possible answers, of which only one is correct, what is the probability that a student …
3. ### statistics

10. A student is taking a multiple choice test where each question have 5 possible answers of which only one is right. If the student knows the answer the student answers correctly, otherwise there is a 20% probability of correct answer. …
4. ### statistics

A student is taking a multiple choice test where each question have 5 possible answers of which only one is right. If the student knows the answer the student answers correctly, otherwise there is a 20% probability of correct answer. …
5. ### Stats

A student takes a 32 question multiple choice exam but did not study and randomly guesses each answer. Each question has three possible choices for the answer. Find the probability that the student guesses more than 75% of the questions …

suppose a student takes a multiple choice test with 10 questions. suppose each question has 4 possible answers. if the student guesses randomly on each questions,what is the probability that the student gets exactly 6 correct?
7. ### stat probability

A multiple choice quiz consists of 20 questions, each with 3 possible equally likely answers. If a student guesses at the answer to each question, then the mean number of correct answers selected by the student is?
8. ### Statistics

A student guesses blindly on a 20-question multiple choice test. If each question has 4 answer choices (only one of which is correct), what is the probability that the student will answer exactly 10 questions correctly?
9. ### Statistics

An unprepared student is about to take his first test of the semester. He is told that his test will be composed of 20 multiple choice questions, each with 4 possible answers, only one of which is correct. a.What is the probability …
10. ### Statistics Algebra 2

A 10-question multiple choice test has 4 possible answers for each question. A student guesses on all ten answer. a)What is the probability that the student selects at least 6 correct answers?

More Similar Questions

Post a New Question