Qus : 2
NIMCET 2027 PYQ
3
An anti-aircraft gun fires a maximum of four shots.
Probabilities of hitting in the 1st, 2nd, 3rd, and 4th shot are
0.4, 0.3, 0.2 and 0.1 respectively.
Find the probability that the gun hits the plane.
1
$0.6972$ 2
$0.6978$ 3
$0.6976$ 4
$0.6974$ Go to Discussion
NIMCET 2027 Previous Year PYQ
NIMCET 2027 NIMCET 2009 PYQ
Solution Hit at least once = 1 − (miss all shots)
Miss probabilities:
1st: $(1 - 0.4) = 0.6$
2nd: $(1 - 0.3) = 0.7$
3rd: $(1 - 0.2) = 0.8$
4th: $(1 - 0.1) = 0.9$
Miss all:
$0.6 \cdot 0.7 \cdot 0.8 \cdot 0.9 = 0.3024$
Hit at least once:
$1 - 0.3024 = 0.6976$
Qus : 4
NIMCET 2027 PYQ
1
A random variable $X$ has the probability distribution:
\[\begin{array}{c|ccccccccc}
x & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 \\
\hline
P(X=x) & a & 3a & 5a & 7a & 9a & 11a & 13a & 15a & 17a
\end{array}
\]The value of $a$ is:
1
$\dfrac{1}{81}$ 2
$\dfrac{2}{82}$ 3
$\dfrac{5}{81}$ 4
$\dfrac{7}{81}$ Go to Discussion
NIMCET 2027 Previous Year PYQ
NIMCET 2027 NIMCET 2011 PYQ
Solution $ \text{Total probability} = 1 $
$ a(1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17) = 1 $
$ 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 = 81 $
$ 81a = 1 $
$ a = \frac{1}{81} $
Qus : 9
NIMCET 2027 PYQ
2
n a Poisson distribution if $P[X=3] = \frac{1}{4} P[X=4]$ then $P[X=5] = k P[X=7]$ where $k$ equals to
1
$ \frac{1}{7} $ 2
$ \frac{21}{128} $ 3
$ \frac{128}{21} $ 4
$ \frac{21}{256} $ Go to Discussion
NIMCET 2027 Previous Year PYQ
NIMCET 2027 NIMCET 2010 PYQ
Solution Poisson PMF:
$P[X=x] = e^{-\lambda} \frac{\lambda^x}{x!}$
Given:
$P(3) = \frac{1}{4} P(4)$
$\frac{\lambda^3/3!}{\lambda^4/4!} = \frac{1}{4}$
$\frac{4}{\lambda} = \frac{1}{4}$
$\lambda = 16$
Now find $k$:
$\frac{P(5)}{P(7)} = \frac{\lambda^5/5!}{\lambda^7/7!} = \frac{7 \cdot 6}{\lambda^2}$
Substitute $\lambda = 16$:
$\frac{42}{256} = \frac{21}{128}$
So,
$k = \frac{21}{128}$
Qus : 12
NIMCET 2027 PYQ
4
Let $X$ and $Y$ be two independent identically distributed Bernoulli random variables with common probability mass function: $P(X=1)=\frac{1}{2}$ and $P(X=0)=\frac{1}{2}$. If $Z=XY$, then the distribution of $Z$ is:
1
Bernoulli with $P(Z=1)=\frac{1}{2}$ and $P(Z=0)=\frac{1}{2}$ 2
Bernoulli with $P(Z=1)=\frac{2}{3}$ and $P(Z=0)=\frac{1}{3}$ 3
Bernoulli with $P(Z=1)=\frac{1}{3}$ and $P(Z=0)=\frac{2}{3}$ 4
Bernoulli with $P(Z=1)=\frac{1}{4}$ and $P(Z=0)=\frac{3}{4}$ Go to Discussion
NIMCET 2027 Previous Year PYQ
NIMCET 2027 NIMCET 2026 PYQ
Solution Given,
$Z=XY$
Now, $Z=1$ only when both $X=1$ and $Y=1$.
Since $X$ and $Y$ are independent,
$P(Z=1)=P(X=1,Y=1)$
$P(Z=1)=P(X=1)P(Y=1)$
$P(Z=1)=\frac{1}{2}\times \frac{1}{2}$
$P(Z=1)=\frac{1}{4}$
Now,
$P(Z=0)=1-P(Z=1)$
$P(Z=0)=1-\frac{1}{4}$
$P(Z=0)=\frac{3}{4}$
Therefore, $Z$ follows Bernoulli distribution with
$P(Z=1)=\frac{1}{4}$ and $P(Z=0)=\frac{3}{4}$
Correct answer is option $4$.
Qus : 13
NIMCET 2027 PYQ
4
For a given sample, the computed values of the variance and fourth central moment are $3$ and $63$ respectively. Then the underlying frequency distribution is classified as:
1
Normal 2
Mesokurtic 3
Platykurtic 4
Leptokurtic Go to Discussion
NIMCET 2027 Previous Year PYQ
NIMCET 2027 NIMCET 2026 PYQ
Solution Given,
Variance $=3$
So,
$\mu_2=3$
Fourth central moment is:
$\mu_4=63$
Coefficient of kurtosis is:
$\beta_2=\frac{\mu_4}{\mu_2^2}$
Substitute the values:
$\beta_2=\frac{63}{3^2}$
$\beta_2=\frac{63}{9}$
$\beta_2=7$
For a normal or mesokurtic distribution,
$\beta_2=3$
Here,
$\beta_2=7>3$
So, the distribution is leptokurtic.Given,
$Z=XY$
Now, $Z=1$ only when both $X=1$ and $Y=1$.
Since $X$ and $Y$ are independent,
$P(Z=1)=P(X=1,Y=1)$
$P(Z=1)=P(X=1)P(Y=1)$
$P(Z=1)=\frac{1}{2}\times \frac{1}{2}$
$P(Z=1)=\frac{1}{4}$
Now,
$P(Z=0)=1-P(Z=1)$
$P(Z=0)=1-\frac{1}{4}$
$P(Z=0)=\frac{3}{4}$
Therefore, $Z$ follows Bernoulli distribution with
$P(Z=1)=\frac{1}{4}$ and $P(Z=0)=\frac{3}{4}$
Correct answer is option $4$.
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