# Challenge Response 162

## Shaking hands

Let's take as x the number of people attending the meeting.

So each of the x people held hands for others (x-1) people. The total handshake of the meeting was x (x-1).

Considering the fact that the handshake between two people should be counted as just one (for example, John gave Mark a hand and Mark gave John a hand), we just count a handshake. We have the following equation:

Rewriting it we have:

Using Bhaskara, we have to .

How x is the number of people attending the meeting, this number cannot be negative.

So at the meeting there were 12 people.

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