<PRE><B>Question 535802</B>
Look at the formula for each:&lt;P&gt;

nPr=n!/(n-r)! = 336 and nCr=n!/r!(n-r)! = 56&lt;P&gt;

That means 336/r! = 56 and r! = 336/56 = 6 = 3*2 * 1 so r = 3.&lt;P&gt;

n!/(n-3)! = 336 = n*(n-1)*(n-2)  (Remember, if the denominator is (n-3)!, it cancels all but the first 3 factors of n!.&lt;P&gt;

Example  8!/(8-3)! = 8*7*6*5*4*3*2*1/5*4*3*2*1= 8*7*6&lt;P&gt;

The easiest way to finish is to try some numbers.  &lt;P&gt;
10:  10*9*8 = 720 (too big)&lt;P&gt;
9:  9*8*7 = 504 (too big)&lt;P&gt;
8:  8*7*6 = 336  (That&#39;s it)&lt;P&gt;
n=8 and r = 3

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