Question

the total number of combination of n different things taken 1,2,3,..,n at a time is ​

Answer 1

Answer:

The number of permutations of n distinct objects, taken r at a time is: Pr = n! / (n - r)! Thus, 210 different 3-digit numbers can be formed from the digits 1, 2, 3, 4, 5, 6, and 7.

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