How do you evaluate $^{7} P_{3}$ $color(white)()^7 P_3$ ?

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Answer 1 · 2016-08-05T11:13:07

$210$ $210$

Written as $^{7} P_{3} \leftarrow Permutation$ $color(white)()^7P_3 larr" Permutation"$

Standard form $.^{n} P_{r} = \frac{n!}{(n - r)!}$ $color(white)(.)^nP_r =(n!)/((n-r)!)$ giving

$(7!)/((7-3)!) = (7xx6xx5xxcancel(4!))/(cancel(4!))$

$=210$

How do you evaluate color(white)()^7 P_37P3color(white)()^7 P_3 ?