If there are 8 people at a party,
- How many possible ways are there for all of them to line up (to get drinks, for example)?
- How many possible ways are there to pick four of those people out of the drink line, keeping them in order?
- How many ways are there to pick a group of 4 out of the 8 (like to play cards)?
- How long would it take for everyone at the party to introduce themselves to everyone else at the party, if an introduction takes 15 seconds?