Question 1149499
You need P( 80,3 ) and P( 60,3 ) to get all
the possible choices for the 3 offices
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Then you need P( 80,3 ) x P( 60,3 ) to get
all the ways to combine the 7th and 8th
grade choices for the 3 offices
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P( 80,3 ) = {{{ 80! / ( 80 - 3 )! }}}
P( 80,3 ) = {{{ 80! / 77! }}}
P( 80,3 ) = {{{ 80*79*78 = 492960 }}}
and
P( 60,3 ) = {{{ 60! / 57! }}}
P( 60,3 ) = {{{ 60*59*58 = 205320 }}}
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P( 80,3 ) x P( 60,3 ) = {{{ 492960*205320 }}}
P( 80,3 ) x P( 60,3 ) = {{{ 101214547200 }}}
101,214,547,200 possible ways
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Definitely get a 2nd opinion on this
( Unless you know what the answer should be )