1981
JEE Advanced
Numerical
IIT-JEE 1981
An anti-aircraft gun can take a maximum of four shots at an enemy plane moving away from it. The probabilities of hitting the plane at the first, second, third and fourth shot are $0.4, 0.3, 0.2$ and $0.1$ respectively. What is the probability that the gun hits the plane?
Correct Answer: $$0.69$$
1979
JEE Advanced
Numerical
IIT-JEE 1979
Six boys and six girls sit in a row randomly. Find the probability that
(i) the six girls sit together
(ii) the boys and girls sit alternately.
(i) the six girls sit together
(ii) the boys and girls sit alternately.
Correct Answer: (i) $${1 \over {132}}$$
<br>(ii) $${1 \over {462}}$$
1978
JEE Advanced
Numerical
IIT-JEE 1978
Balls are drawn one-by-one without replacement from a box containing $2$ black, $4$ white and $3$ red balls till all the balls are drawn. Find the probability that the balls drawn are in the order $2$ black, $4$ white and $3$ red.
Correct Answer: $${1 \over {1260}}$$
1994
JEE Advanced
Numerical
IIT-JEE 1994
If two events $A$ and $B$ are such that $P\,\,\left( {{A^c}} \right)\,\, = \,\,0.3,\,\,P\left( B \right) = 0.4$ and $P\left( {A \cap {B^c}} \right) = 0.5,$ then $P\left( {B/\left( {A \cup {B^c}} \right)} \right.$$\left. \, \right] = $ ............
Correct Answer: $$1/4$$
1992
JEE Advanced
Numerical
IIT-JEE 1992
Three faces of a fair die are yellow, two faces red and one blue. The die is tossed three times. The probability that the colours, yellow, red and blue, appear in the first, second and the third tosses respectively is ...............
Correct Answer: $$1/36$$
1991
JEE Advanced
Numerical
IIT-JEE 1991
If the mean and the variance of binomial variate $X$ are $2$ and $1$ respectively, then the probability that $X$ takes a value greater than one is equal to ...............
Correct Answer: $$11/16$$
1990
JEE Advanced
Numerical
IIT-JEE 1990
Let $A$ and $B$ be two events such that $P\,\,\left( A \right)\,\, = \,\,0.3$ and $P\left( {A \cup B} \right) = 0.8.$ If $A$ and $B$ are independent events then $P(B)=$ ................
Correct Answer: $$5/7$$
1989
JEE Advanced
Numerical
IIT-JEE 1989
A pair of fair dice is rolled together till a sum of either $5$ or $7$ is obtained. Then the probability that $5$ comes before $7$ is ...............
Correct Answer: $$2/5$$
1988
JEE Advanced
Numerical
IIT-JEE 1988
Urn $A$ contains $6$ red and $4$ black balls and urn $B$ contains $4$ red and $6$ black balls. One ball is drawn at random from urn $A$ and placed in urn $B$. The one ball is drawn at random from urn $B$ and placed in urn $A$. If one ball is now drawn at random from urn $A$, the probability that it is found to be red is ................
Correct Answer: $$32/55$$
1986
JEE Advanced
Numerical
IIT-JEE 1986
If ${{1 + 3p} \over 3},\,\,\,{{1 - p} \over 4}$ and $\,{{1 - 2p} \over 2}$ are the probabilities of three mutually exclusive events, then the set of all values of $p$ is ..............
Correct Answer: $${1 \over 3} \le p \le {1 \over 2}$$
1985
JEE Advanced
Numerical
IIT-JEE 1985
A box contains $100$ tickets numbered $1, 2, ....., 100.$ Two tickets are chosen at random. It is given that the maximum number on the two chosen tickets is not more than $10.$ The minimum number on them is $5$ with probability ........
Correct Answer: $$1/9$$
1985
JEE Advanced
Numerical
IIT-JEE 1985
$P\left( {A \cup B} \right) = P\left( {A \cap B} \right)$ if and only if the relation between $P(A)$ and $P(B)$ is .............
Correct Answer: $$P(A)$$ $$=$$ $$P(B)$$
1981
JEE Advanced
Numerical
IIT-JEE 1981
For a biased die the probabilities for the different faces to turn up are given below :
This die tossed and you are told that either face $1$ or face $2$ has turned up. Then the probability that it is face $1$ is ...............
Correct Answer: $${5 \over {21}}$$
1989
JEE Advanced
MCQ
IIT-JEE 1989
If the probability for $A$ to fail in an examination is $0.2$ and that for $B$ is $0.3$, then the probability that either $A$ or $B$ fails is $0.5$
A.
TRUE
B.
FALSE
1983
JEE Advanced
MCQ
IIT-JEE 1983
If the letters of the word "Assassin" are written down at random in a row, the probability that no two S's occur together is $1/35$
A.
TRUE
B.
FALSE