The first one is C(12,5) or 12C5 in your notation
Does it really matter in which order he buys the lunches? NO, so you have a combination
and your answer is 792
but in 2) it does matter which person gets which lunch, so you are correct in 5! or 120 ways
A sandwich shop sells 12 different kinds of sandwiches.
1. You want to buy 5 different sandwiches to bring home to your family. How many ways are there to choose the 5 sandwiches that you will buy?
Would it be 12P5 which is equal to 12*11*10*9*8 = 95,040 ways.
2. Once you get home, you have to distribute the five different sandwiches to your four family members and yourself. How many ways are there for you to do this?
Would this be 5*4*3*2*1 or 5P5 = 120 different ways.
1 answer
3 answers