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Thirteen guests have participated in a dinner. The number of handshakes that happened in the dinner is:

#### Options

715

78

286

13

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#### Solution

**78**

**Explanation:**

To handshakes, we need two guests.

Number of selecting 2 guests from 13 is 13C_{2} = `(13 xx 12)/(2 xx 1)` = 78

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