1
IIT-JEE 2006
MCQ (Single Correct Answer)
+5
-1.25
There are $$n$$ urns, each of these contain $$n+1$$ balls. The ith urn contains $$i$$ white balls and $$(n+1-i)$$ red balls. Let $${u_i}$$ be the event of selecting ith urn, $$i=1,2,3........,n$$ and $$w$$ the event of getting a white ball.

Let $$P\left( {{u_i}} \right) = {1 \over n},$$ if $$n$$ is even and $$E$$ denotes the event of choosing even numbered urn, then the value of $$P\left( {w/E} \right)$$ is

A
$${{n + 2} \over {2n + 1}}$$
B
$${{n + 2} \over {2\left( {n + 1} \right)}}$$
C
$${n \over {n + 1}}$$
D
$${1 \over {n + 1}}$$
2
IIT-JEE 2006
MCQ (Single Correct Answer)
+5
-1.25
There are $$n$$ urns, each of these contain $$n+1$$ balls. The ith urn contains $$i$$ white balls and $$(n+1-i)$$ red balls. Let $${u_i}$$ be the event of selecting ith urn, $$i=1,2,3........,n$$ and $$w$$ the event of getting a white ball.

If $$P\left( {{u_i}} \right) = c,$$ (a constant) then $$P\left( {{u_n}/w} \right) = $$

A
$${2 \over {n + 1}}$$
B
$${1 \over {n + 1}}$$
C
$${n \over {n + 1}}$$
D
$${1 \over 2}$$
3
IIT-JEE 2005 Screening
MCQ (Single Correct Answer)
+2
-0.5
A six faced fair dice is thrown until $$1$$ comes, then the probability that $$1$$ comes in even no. of trials is
A
$$5/11$$
B
$$5/6$$
C
$$6/11$$
D
$$1/6$$
4
IIT-JEE 2004 Screening
MCQ (Single Correct Answer)
+2
-0.5
If three distinct numbers are chosen randomly from the first $$100$$ natural numbers, then the probability that all three of them are divisible by both $$2$$ and $$3$$ is
A
$$4/25$$
B
$$4/35$$
C
$$4/33$$
D
$$4/1155$$
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