Problem: A total of 28 handshakes were exchanged at the conclusion of a party. Assuming that each participant was equally polite toward all the others, the number of people present was:
Answer Choices:
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Solution:
Let be the number of people present. Single out a particular individual . shakes hands with persons, and this is true for each of the persons. Since each handshake is between two persons, the total number of handshakes is ;
or