A test consists of 6 multiple choice question | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The total number of questions is $n = 6$.We need to choose $4$ questions to be answered correctly out of $6$,which can be done in ${}^{6}C_{4}$ wa

Vedclass · Accepted Answer

$135$

Vedclass · Answer

(A) The total number of questions is $n = 6$.We need to choose $4$ questions to be answered correctly out of $6$,which can be done in ${}^{6}C_{4}$ ways.For each of the $4$ correct questions,there is only $1$ way to choose the correct answer.For each of the remaining $2$ questions $(6 - 4 = 2)$,the candidate must choose an incorrect answer. Since there are $4$ alternatives and only $1$ is correct,there are $3$ incorrect options for each question.Thus,the number of ways is ${}^{6}C_{4} 	imes (1)^4 	imes (3)^2$.${}^{6}C_{4} = \frac{6 	imes 5}{2 	imes 1} = 15$.Number of ways = $15 	imes 1 	imes 9 = 135$.

$A$ test consists of $6$ multiple choice questions,each having $4$ alternative answers of which only one is correct. The number of ways in which a candidate answers all $6$ questions such that exactly $4$ of the answers are correct is:

Similar Questions

Six balls are drawn successively from an urn containing $7$ red and $9$ black balls. Determine whether or not the trials of drawing balls are Bernoulli trials when the ball drawn is not replaced in the urn after each draw.

It is known that $10 \%$ of certain articles manufactured are defective. What is the probability that in a random sample of $12$ such articles,$9$ are defective?

Five cards are drawn successively with replacement from a well-shuffled deck of $52$ cards. What is the probability that none is a spade?

The mean and the variance of a binomial distribution are $4$ and $2$ respectively. Then the probability of $2$ successes is

If three dice are thrown together,then the probability of getting $5$ on at least one of them is

Vedclass Test Series

Exam Paper Generator

Online Exam Module