document.write( "Question 373028: if i have 20 coins only dimes and quarters and have $3.80 how many quters do i have \n" ); document.write( "

Algebra.Com's Answer #265613 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"d\"$ = number of dimes
\n" ); document.write( "Let $\"q\"$ = number of quarters
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"d+%2B+q+=+20\"$
\n" ); document.write( "(2) $\"10d+%2B+25q+=+380\"$ (in cents)
\n" ); document.write( "-------------------------------
\n" ); document.write( "Multiply both sides of (1) by $\"10\"$
\n" ); document.write( "and subtract (1) from (2)
\n" ); document.write( "(2) $\"10d+%2B+25q+=+380\"$
\n" ); document.write( "(1) $\"-10d+-+10q+=+-200\"$
\n" ); document.write( " $\"15q+=+180\"$
\n" ); document.write( " $\"q+=+12\"$
\n" ); document.write( "And, from (1),
\n" ); document.write( " $\"d+%2B+12+=+20\"$
\n" ); document.write( " $\"d+=+8\"$
\n" ); document.write( "I have 8 dimes and 12 quarters
\n" ); document.write( "check answer:
\n" ); document.write( "(2) $\"10d+%2B+25q+=+380\"$
\n" ); document.write( "(2) $\"10%2A8+%2B+25%2A12+=+380\"$
\n" ); document.write( " $\"80+%2B+300+=+380\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

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