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OpenStudy (anonymous):
i bet
OpenStudy (anonymous):
me too
OpenStudy (anonymous):
lets go slow
OpenStudy (anonymous):
okay
OpenStudy (anonymous):
if all the letters were different (they are not, but i am pretending) there would be
6 choices for the first letter
5 for the second
4 for the third
3 for the fourth
2 for the fifth and
1 for the sixth
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OpenStudy (anonymous):
by the counting principle the number of ways to do this is found by multiplying all the choices together, i.e.
\[6\times 5\times 4\times 3\times 2\times 1=6!\]
OpenStudy (anonymous):
so it is 360
OpenStudy (anonymous):
but in this case you have repeated letters
there are two E and two T so you have overcounted
OpenStudy (anonymous):
you have to divide by 2 twice, because of this
OpenStudy (anonymous):
why do u divide by 2 twice?
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OpenStudy (anonymous):
so the answer is
\[\frac{6\times 5\times 4\times 3\times 2}{4}=6\times 5\times 3\times 2\]
OpenStudy (anonymous):
because there are two E and also two T
OpenStudy (anonymous):
i get 180
OpenStudy (anonymous):
i get all of it except why divide by 4
OpenStudy (anonymous):
could u go into depth
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OpenStudy (anonymous):
because for example
\[E_1BE_2T_1T_2R\] looks the same as
\[E_2BE_1T_1T_2R\] looks the same as
\[E_1BE_2T_2T_1R\] looks the same as
\[E_2BE_1T_2T_1R\] without the subscripts
OpenStudy (anonymous):
the \(6!\) counts these as different, but in fact they are the same
\(6!\) overcounts by a factor of 4