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Udemy Ka course liya huva h

Permutation And Combination's

• Factorial : $5!=5 * 4 * 3 * 2 * 1$ = 120

Arrangement

• to arrange n things in a line → $n!$ ways
• to arrange n things in a circle → $(n-1)!$  ways

Formula

Select (C→ combination)

Select and Arrange (P → Permutation)

• $^nCr=n! / r! (n-r)!$
• $^nPr=n! / (n-r)!$