Question 144475
{{{P(n,5) = 20P(n,3)}}} 

{{{8nPr 5 = 20 * 8 nPr 3}}} ==> 

{{{8nPr 5 = 8!/3! = 8 x 7 x 6 x 5 x 4 = 6720}}}

{{{8nPr3 = 8 x 7 x 6 = 336}}}

 so {{{20 * 336 = 6720}}}

Therefore, {{{8nPr 5 = 20 * 8 nPr 3}}}


{{{P(n,5) = 20P(n,3)}}} is true when {{{n = 8}}}