document.write( "Question 274991: Andy has 21 coins made up of quarters and half dollars, and their total value is $6.50. How many quarters does he have? \n" ); document.write( "

Algebra.Com's Answer #200661 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"q\"$ = number of quarters
\n" ); document.write( "Let $\"h\"$ = number of half dollars
\n" ); document.write( "---------------------
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"h+%2B+q+=+21\"$
\n" ); document.write( "(2) $\"50h+%2B+25q+=+650\"$ (in cents)
\n" ); document.write( "--------------------------
\n" ); document.write( "Multiply both sides of (1) by $\"25\"$
\n" ); document.write( "and subtract from (2)
\n" ); document.write( "(2) $\"50h+%2B+25q+=+650%7D%0D%0A%281%29+%7B%7B%7B-25h+-+25q+=+525\"$
\n" ); document.write( " $\"25h+=+125\"$
\n" ); document.write( " $\"h+=+5\"$
\n" ); document.write( "And, since
\n" ); document.write( "(1) $\"h+%2B+q+=+21\"$
\n" ); document.write( " $\"5+%2B+q+=+21\"$
\n" ); document.write( " $\"q+=+16\"$
\n" ); document.write( "There are 16 quarters and 5 half dollars
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"50h+%2B+25q+=+650\"$
\n" ); document.write( " $\"50%2A5+%2B+25%2A16+=+650\"$
\n" ); document.write( " $\"250+%2B+400+=+650\"$
\n" ); document.write( " $\"650+=+650\"$
\n" ); document.write( "OK \n" ); document.write( "

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