Warm Up Solutions

Solve without a calculator. Show your work.

  1. nCr(12, 2)

12!2!122!=126·11·10!2·110!=66

  1. nCr(12, 3)

12!3!123!=122·11·10·9!3·2·19!=220

Note

Q: What is the difference between a permutation and a combination?

A: The order matters in a permutation, and order does not matter in a combination.

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