Probability · NDA previous year questions

2024 28 questions

1. Q1152024 · 21 Apr 2024

   Consider the following for the next two (02) items that follow: An unbiased coin is tossed $n$ times. The probability of getting at least one tail is $p$ and the probability of at least two tails is $q$ and $p-q=\frac{5}{32}$. What is the value of $n$?

   1. A.4
   2. B.5
   3. C.6
   4. D.7
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   Answer: B

2. Q1162024 · 21 Apr 2024

   Consider the following for the next two (02) items that follow: An unbiased coin is tossed $n$ times. The probability of getting at least one tail is $p$ and the probability of at least two tails is $q$ and $p-q=\frac{5}{32}$. What is the value of $p+q$?

   1. A.$\frac{57}{32}$
   2. B.$\frac{53}{32}$
   3. C.$\frac{51}{32}$
   4. D.1
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   Answer: A

3. Q1172024 · 21 Apr 2024

   Consider the following for the next two (02) items that follow: $$\begin{array}{cccccc}{x}_i& 1& 2& 3& \dots & n\\ f_i& 1& 2^{-1}& 2^{-2}& \dots & 2^{-(n-1)}\end{array}$$ What is ${\sum }_i^n{x}_i{f}_i$ equal to?

   1. A.$\frac{2^{n+1}-n+2}{2^{n-1}}$
   2. B.$\frac{2^{n+1}-n-2}{2^{n-1}}$
   3. C.$\frac{2^{n+1}+n+2}{2^{n-1}}$
   4. D.$\frac{2^{n+1}-n-2}{2^n}$
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   Answer: B