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TCS NQT GuideTCS NQT Numerical AbilityPermutations and Combinations (P&C) Formula Cheat Sheet

Permutations and Combinations (P&C) Formula Cheat Sheet

Learn core concepts, essential formulas, and attempt practice questions designed on the latest TCS NQT testing patterns.

Key Concepts & Formulas

  • 1Factorial: n! = n * (n-1) * ... * 1.
  • 2Permutations (Arrangement): nPr = n! / (n-r)!.
  • 3Combinations (Selection): nCr = n! / [r! * (n-r)!].
  • 4Relation: nPr = r! * nCr.
  • 5Arranging circular items: (n - 1)!.

TCS NQT Style Practice Questions

Practice Question 1

In how many ways can a committee of 3 members be selected from a group of 5 people?

A) 10
B) 60
C) 15
D) 20

Correct Answer: A) 10

Step-by-step Solution: Use combinations selection: 5C3 = 5! / (3! * 2!) = (5 * 4) / 2 = 10.

Practice Question 2

How many different 4-letter words can be formed from letters of the word 'BLUE'?

A) 24
B) 12
C) 4
D) 256

Correct Answer: A) 24

Step-by-step Solution: The word has 4 distinct letters. Number of arrangements = 4! = 4 * 3 * 2 * 1 = 24.

Study Pro-Tip

Use combinations (nCr) for choosing, and permutations (nPr) when order of arrangement matters.

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