document.write( "Question 1163219: If nPr = 336 and nCr = 56, find n and r. \r
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Algebra.Com's Answer #787237 by ikleyn(52782) $\"\"$ $\"About$

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document.write( "The ratio of these quantities,  nPr and nCr, is  n*(n-1)* . . . *(n-r+1) :   and equals to r!;\r\n" );
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document.write( "so,  r! =  = 6.\r\n" );
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document.write( "Hence, r = 3.\r\n" );
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document.write( "Next,  nPr at r = 3 is  n*(n-1)*(n-2) = 336.\r\n" );
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document.write( "After several simple trials and errors you get  n = 8.\r\n" );
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document.write( "You may also use  (n-1) ~  = 6.95 (approx.)\r\n" );
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document.write( "ANSWER.  n = 8,  r = 3.\r\n" );
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