### Home > CCA2 > Chapter 10 > Lesson 10.3.1 > Problem 10-150

The Spirit Club recently got a call from the school executive council, asking them to make a committee. They now have

Al had a thought:

*“I remember that the number of three-person committees you can select from*How would you calculate this number?volunteers is . This would be the number of committees the tenth volunteer will NOT be on because he or she would be selected from the other nine members.” *“I also know how many committees the new volunteer WILL be on because I can just add his name to each of the two-member committees I had already selected from*How many possible committees would include the tenth volunteer?.” _{ }? Without using a calculator (and without multiplying or dividing), explain how Al used parts (a) and (b) to calculate

. Add your answers from parts (a) and (b).

How is this related to Pascal’s Triangle?

How do you get from one row to the next when writing out Pascal's Triangle?