5 people meet for a business lunch. Each person shakes hands once with each other person present. How many handshakes take place?	Pick.
A) 30
B) 21
C) 10
D) 15
E) 12
the formula to count handshakes is n(n−1)2n(n−1)2   Where n is the number of people   =&gt; 5(5-1)/2 = 5*4/2 = 20/2= 
<gadget id="calculator">20/2</gadget>
<output>10</output>
10=&gt; the answer is 10(10)
<result>C</result>
5 people meet for a business lunch. Each person shakes hands once with each other person present. How many handshakes take place?