I was scrolling thru some posts by tetre, and I found this https://web2.0calc.com/questions/help-please_4429

The solution given was really good, but I just wanted to say that there's a much easier way: It's \(2^9 \cdot 10\) = \(5120\) ways!

This is because each member has 2 options: Either be on the committee or not.

And the 10 is just choices for the chairman! :)

CentsLord Aug 29, 2020