document.write( "Question 1030226: please help Me These Questions
\n" ); document.write( "1.what will be the value of \"r\",if P(7,r)=60*P(7,r-3)
\n" ); document.write( "2.what will be the value of \"n\",if 3*P(2n+4,3)=2*P(n+4,4)
\n" ); document.write( "3.Find \"n\" if 3*P(n,4)=2*P(n-1,5)
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Algebra.Com's Answer #645162 by rothauserc(4718) $\"\"$ $\"About$

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P(n,r) = nPr = n! / (n-r)!
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\n" ); document.write( "1) P(7,r) = 7Pr = 7! / (7-r)!
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\n" ); document.write( "60 * P(7, r-3) = 7! / (10-r)!
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\n" ); document.write( "7! / (7-r)! = 60 * 7! / (10-r)!
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\n" ); document.write( "1 / (7-r)! = 60 / (10-r)!
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\n" ); document.write( "cross multiply fractions
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\n" ); document.write( "(10-r)! = 60 * (7-r)!
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\n" ); document.write( "(10-r)(9-r)(8-r)(7-r)(6-r) * ... = 60 * (7-r)* (6-r) * (5-r) * ...
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\n" ); document.write( "(10-r)(9-r)(8-r) = 60
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\n" ); document.write( "r can be at most 7, trial and error finds r = 5
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\n" ); document.write( "2 and 3 use the same method
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