Math
posted by Danielle .
A sociology seminar has 7 members
(a) They begin each meeting with each member shaking hands with all the other members. No one shakes another member's hand twice. How many handshakes take place?
(b)The professor shakes hands with each member of the seminar and in a different sequence each time. How many sequences of handshakes are possible?
sequences

a) how about C(7,2) = 21
b) You mean only the prof shakes hands?
And he does it again and again?? Silly question, anyway....
In one specific sequence there are 7 handshakes
if the prof shakes hands with each of the 7 members.
Now if we "arrange" that sequence in all its permutations,
the total number possible sequences = 7! = 5040 
in a seminar there were twelve people. if each shook their hand all others,how many times were the hands shaken altogether?