document.write( "Question 947343: A bag contains 15 coins. Each coin is a penny,
\n" ); document.write( "nickel, dime or quarter. The total value of these
\n" ); document.write( "coins is $2.16. There is at least one coin of
\n" ); document.write( "each denomination, and the number of pennies,
\n" ); document.write( "nickels, dimes and quarters are all distinct. If
\n" ); document.write( "there are 5 dimes, how many nickels are in the bag?
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Algebra.Com's Answer #578004 by josgarithmetic(39618)\"\" \"About 
You can put this solution on YOUR website!
SEE BELOW, IMPROVEMENT/ALTERNATIVE\r
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\n" ); document.write( "\n" ); document.write( "p, n, d, q;
\n" ); document.write( "p+n+d+q=15.
\n" ); document.write( "0.01p+0.05n+0.1d+0.25q=2.16.
\n" ); document.write( "d=5.\r
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\n" ); document.write( "\n" ); document.write( "Simplify the money count.
\n" ); document.write( "\"p%2B5n%2B10d%2B25q=216\"
\n" ); document.write( "and substitute for d;
\n" ); document.write( "\"p%2B5n%2B10%2A5%2B25q=216\"
\n" ); document.write( "\"p%2B5n%2B25q=166\"\r
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\n" ); document.write( "\n" ); document.write( "You have a system,
\n" ); document.write( "\"system%28p%2B5n%2B25q=166%2Cp%2Bn%2B5%2Bq=15%29\"
\n" ); document.write( "which is
\n" ); document.write( "\"system%28p%2B5n%2B25q=166%2Cp%2Bn%2Bq=10%29\"\r
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\n" ); document.write( "\n" ); document.write( "You can assume any one of p, or n, or q is constant, and then solve for the other two variables in terms of the chosen constant. This is because you are assuming a two-variable, linear system.\r
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\n" ); document.write( "\n" ); document.write( "As a guess, the number of quarters is probably not too large compared to the 15 count of coins. Assign k=q.\r
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\n" ); document.write( "\n" ); document.write( "-
\n" ); document.write( "\"system%28p%2B5n=166-25k%2Cp%2Bn=10-k%29\"
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\n" ); document.write( "E1-E2,
\n" ); document.write( "\"4n=%28166-25k%29-%2810-k%29\"
\n" ); document.write( "\"4n=166-10-25k%2Bk\"
\n" ); document.write( "\"4n=156-24k\"
\n" ); document.write( "\"n=39-6k\"
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\n" ); document.write( "Try to find p based on this formula for n.
\n" ); document.write( "\"p%2Bn=10-k\"
\n" ); document.write( "\"p=10-k-n\"
\n" ); document.write( "\"p=10-k-%2839-6k%29\"
\n" ); document.write( "\"p=10-39-k%2B6k\"
\n" ); document.write( "\"p=-29%2B7k\"
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\n" ); document.write( "What will make sense for k? In summary, we have a formula for p and a formula for n:
\n" ); document.write( "\"system%28n=39-6k%2Cp=7k-29%29\".
\n" ); document.write( "We must have natural numbers for each of n, p, k. None of them be equal. None of them over 13.\r
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\n" ); document.write( "\n" ); document.write( "Choose and find.\r
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\n" ); document.write( "\n" ); document.write( "k__________n________p
\n" ); document.write( "1__________33_______-22
\n" ); document.write( "2__________27_______-15
\n" ); document.write( "3__________21_______-8
\n" ); document.write( "4__________15_______-1
\n" ); document.write( "5__________9________6, still not good because need some nickels, 9+6=15.
\n" ); document.write( "6__________3________13
\n" ); document.write( "7__________-3
\n" ); document.write( "FAILED TO RESOLVE THE PROBLEM...........................\r
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\n" ); document.write( "\n" ); document.write( "IMPROVEMENT/ALTERNATIVE:
\n" ); document.write( "Re-examining the description, the two key equations are
\n" ); document.write( "\"system%28p%2B5n%2B25q=166%2Cp%2Bn%2Bq=10%29\"
\n" ); document.write( "which are based on the given assignment that d=5.\r
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\n" ); document.write( "\n" ); document.write( "Subtracting the coin count equation from the money count equation (both being in their just stated simplified form), we have
\n" ); document.write( "\"4n%2B24q=156\"
\n" ); document.write( "\"highlight_green%28n%2B6q=39%29\"
\n" ); document.write( "and p has been eliminated.\r
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\n" ); document.write( "\n" ); document.write( "Using this simple equation relating n and q, try choosing different natural number values for q and find resulting n, and look for results which makes sense.\r
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\n" ); document.write( "\n" ); document.write( "pick q____________find n
\n" ); document.write( "1_________________33
\n" ); document.write( "2_________________27
\n" ); document.write( "3_________________21
\n" ); document.write( "4_________________15
\n" ); document.write( "5_________________9
\n" ); document.write( "6_________________3--------THERE!!! Their sum is only 9, allowing the....five dimes.\r
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\n" ); document.write( "\n" ); document.write( "ANSWER RESULT
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\n" ); document.write( "Combination appears to be:
\n" ); document.write( "p=?
\n" ); document.write( "n=3
\n" ); document.write( "d=5
\n" ); document.write( "q=6
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\n" ); document.write( "p=15-3-5-6=1, because total coins must be 15
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\n" ); document.write( "Notice all counts are unequal.
\n" ); document.write( "One penny, three nickels, five dimes, six quarters.
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