Review Permutations with Shirley and Aaron! (Video)
part 1
1. How many different ways can we mark off the 30 days of November on our calendar if we have 10 different colored crayons to use and we only use one color per day?
This is 10 choices for the first day, 10 choices for the second day, etc. until the thirtieth day, which is
10 x 10 x 10 x ... x 10 = 10^30.
part 2
2. How many ways can Lina build up an ice cream cone that always consists of 4 different flavors (ordered one on top of another) if she has 12 possible flavors to choose from?
She has 12 choices for the first flavor, 11 choices for the 2nd one, 10 choices for the 3rd one, and 9 choices for the 4th. This is 12 x 11 x 10 x 9 = 11880.