# I've forgotten how to do this type of question? Question below...

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Find an expression for the total number of handshakes needed if #n# people all shake hands with each other.

Find an expression for the total number of handshakes needed if

##### 1 Answer

May 22, 2018

#### Explanation:

** Note that this explanation might be confusing. **

Let's say three people shook hands with each other. Their names are A, B, C, and D.

A: B, C, D

B: A, C, D

C: A, B, D

D: A, B, C

Some are counted more than once. Cross them out.

A: B, C, D

B: C, D

C: D

D:

That is