Question

How to calculate permutation and combination?

Answer 1

They both have their formulas
C(n, r) = n! P(n, r) = n!
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r ! (n-r) ! ( n-r ) !
Example :a ball contains 100 bingo no. How many possible ways are three for picking different numbers.
Solution : 100! C= n! 100
- - - - - - - - - - - - - - - = - - - - - - - =
5! (100-5)! R! (n-r)! 5!(100-5)!
75,287,520