6 people meet for a meeting. Each person shakes hands once with each other person present. How many handshakes take place?  Choices:  A) 30  B) 21  C) 18  D) 15  E) 10
Let's look at the logic.   Every person shakes hand with other '5'. So, 6 people shake hands with 6X5= 30 people   But in this 30 we have counted two times the total handshakes (e shakes hand with f and f shakes hand with e)   So just divide 30/2= 
<gadget id="calculator">30/2</gadget>
<output>15</output>
15 total handshakes   Answer is 15
<result>D</result>
6 people meet for a meeting. Each person shakes hands once with each other person present. How many handshakes take place?