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Indian Navy SSR (Sailor) Permutations and Combinations — practice questions

Explore 78 free Permutations and Combinations questions in Indian Navy SSR (Sailor) Mathematics. Open each question or exercise to read its content, reference answers and available explanation.

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Permutations and Combinations questions and exercises with answers

Showing questions 1–30 of 78.

The number of ways to arrange $n$ distinct objects in a row is:Read the answer and worked solution →A **discrete** random variable is one whose possible values:Read the answer and worked solution →tan(45°) equals:Read the answer and worked solution →The arithmetic mean of n values x1, x2, ..., xn is:Read the answer and worked solution →The distance between two points $P(x_1,y_1)$ and $Q(x_2,y_2)$ is:Read the answer and worked solution →The angle 90° in radians is:Read the answer and worked solution →Sort each inverse function into its domainRead the answer and worked solution →Tap every function whose domain is [−1, 1]Read the answer and worked solution →Match each inverse function to its domainRead the answer and worked solution →Match each inverse function to its principal value branchRead the answer and worked solution →Flip and pair: function with its principal rangeRead the answer and worked solution →Which principal ranges sit around zero, and which run 0 to π?Read the answer and worked solution →Tap every function whose principal range has a point removedRead the answer and worked solution →Name the principal value branchRead the answer and worked solution →Domain checkRead the answer and worked solution →Put the reasoning in order: why an inverse needs a restricted domainRead the answer and worked solution →True or false: existence of inversesRead the answer and worked solution →True or false: reading the tableRead the answer and worked solution →Spot the one that does not belongRead the answer and worked solution →Two are true, one is notRead the answer and worked solution →Assertion and reasonRead the answer and worked solution →Complete the summary tableRead the answer and worked solution →Complete the rule about restricting a domainRead the answer and worked solution →Three of these are wrong. Find the one that holds.Read the answer and worked solution →Principal values worked in the chapterRead the answer and worked solution →Order the steps for finding a principal valueRead the answer and worked solution →True or false: principal valuesRead the answer and worked solution →Match each identity to the condition it needsRead the answer and worked solution →Assertion and reason: identitiesRead the answer and worked solution →Match each mathematician to the year your syllabus givesRead the answer and worked solution →

Worked practice questions

The number of ways to arrange $n$ distinct objects in a row is:

  1. $2^n$
  2. $n$
  3. $n!$
  4. $n^2$
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Correct answer: C. $n!$

Arrangements of $n$ distinct objects in a row: $n$ choices for the first position then $n-1$ for the second, $n-2$ for the third, etc. By the multiplication principle: $n \times (n-1) \times \ldots \times 1 = n!$ For 5 books on a shelf: $5! = 120$ arrangements. For 10 students in a line: $10! = 3,628,800$.

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A **discrete** random variable is one whose possible values:

  1. Are finite or countably infinite
  2. Form an interval of real numbers (uncountably infinite)
  3. Are always negative
  4. Are obtained only by measurement
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Correct answer: A. Are finite or countably infinite

**Discrete RV:** finite or countably infinite values (typically non-negative integers — number of heads, defective items, etc.). Continuous RV has uncountably infinite values forming an interval.

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tan(45°) equals:

  1. ∞
  2. 0
  3. 1
  4. √3
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Correct answer: C. 1

We have tan(45°) = sin(45°)/cos(45°). That is tan(45°) = (1/√2)/(1/√2). So tan(45°) = 1.

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