Permutations and combinations Questions answers by Wisdom helps

Permuations & Combinations Important Questions

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Concepts & Formulas

• Permutation ($nPr$):Permutation means arranging objects in a specific order.
  nPr = n! / (n-r)!

Shortcut Trick:
Whenever position / order / ranking / arrangement is mentioned → use Permutation

• Combination ($nCr$): Combination means selecting objects where order does not matter.
  Shortcut Trick
  Whenever selection / group / committee / choosing is mentioned → use Combination
  nCr = n! / [r!(n-r)!]

Concept	Permutation	Combination
Meaning	Arrangement	Selection
Order	Important	Not Important
Formula	nPr = n! / (n-r)!	nCr = n! / r!(n-r)!
Used In	Seating, Ranking	Committee, Group
Example	AB ≠ BA	AB = BA
Shortcut	P → Position	C → Choose