document.write( "Question 157929: How can I make $5.11 out of 31 coins? I can only use pennies and quarters \n" ); document.write( "

Algebra.Com's Answer #116363 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let's call the pennies P and quarter Q.
\n" ); document.write( "Each penny is worth $0.01 and each quarter $0.25.
\n" ); document.write( "Total number of coins is 31.
\n" ); document.write( "1.P+Q=31
\n" ); document.write( "Total value of coins is $5.11.
\n" ); document.write( "2.$0.01*P+$0.25*Q=$5.11
\n" ); document.write( "Let's multiply both sides of eq. 2 by 100 to get rid of decimals.
\n" ); document.write( "2. $\"P%2B25Q=511\"$
\n" ); document.write( "From eq. 2,
\n" ); document.write( "2. $\"P%2B25Q=511\"$
\n" ); document.write( " $\"P=511-25Q\"$
\n" ); document.write( "Substitute this expression into eq. 1 and solve for Q.
\n" ); document.write( "1. $\"P%2BQ=31\"$
\n" ); document.write( " $\"%28511-25Q%29%2BQ=31\"$
\n" ); document.write( " $\"-24Q=31-511\"$
\n" ); document.write( " $\"-24Q=-480\"$
\n" ); document.write( " $\"highlight%28Q%29=20\"$
\n" ); document.write( "from above
\n" ); document.write( " $\"P=511-25Q\"$
\n" ); document.write( " $\"P=511-25%2820%29\"$
\n" ); document.write( " $\"P=511-500\"$
\n" ); document.write( " $\"highlight%28P%29=11\"$
\n" ); document.write( "11 pennies abd 20 quarters. \n" ); document.write( "

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