Question

20 people show up to a post-PSTAT 120A party. If everyone shakes hands with everyone else, how many handshakes take place

Answer 1

Answer: There are 190 handshakes takes place.

Step-by-step explanation:

Since we have given that

Number of people in the party = 20

Here, n = 20

So, the number of handshakes would be

$\dfrac{n(n-1)}{2}\\\\=\dfrac{20(20-1)}{2}\\\\=\dfrac{20\times 19}{2}\\\\=10\times 19\\\\=190$

Hence, there are 190 handshakes takes place.