If 10 persons meet at a reunion and each person shakes hands exactly once with each of the others, what is the total number of handshakes?	Pick one.
A) 11 × 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1  B) 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1  C) 11 × 10  D) 55  E) 45
If 10 persons meet at a reunion and each person shakes hands exactly once with each of the others, what is the total number of handshakes?   1st person will have 9 handshakes, 2nd will have 8, ....9th will have 1 and 10th will have 0   = 9+8+7+6+5+4+3+2+1= 
<gadget id="calculator">9+8+7+6+5+4+3+2+1</gadget>
<output>45</output>
45   if we generalize this: if there are n people then there will be n(n-1)/2 handshakes.   Ans.45) 45
<result>E</result>
If 10 persons meet at a reunion and each person shakes hands exactly once with each of the others, what is the total number of handshakes?