Posted by Shay on Monday, August 25, 2008 at 4:49pm.
seven people meet and shake hands with eachother how many handshakes occur?
(second question)
using inductive reasoning, write a formula for the number of handshakes if the number of people is n

Math  Damon, Monday, August 25, 2008 at 6:57pm
combinations of n objects taken r at a time
C(n,r) = n!/[r!(nr!)]
C(7,2) = 7!/[2!(5!)]
=7*3
=21
ok, reasoning
first person shakes with 6
second person with 5
third with 4
.
.
.
6th with 1
so
6+5+4+3+2+1 = 21 sure enough

Math  Lun, Saturday, October 1, 2016 at 1:01pm
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