document.write( "Question 808802: Mrs. Sanders had 80 coins. Some of them were $1.00 coins and the rest were .50 cent coins. The total amount added up to $50.00. How many coins of each kind were there? \n" ); document.write( "

Algebra.Com's Answer #487271 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+a+\"$ = number of $1 coins
\n" ); document.write( "Let $\"+b+\"$ = number of $.50 coins
\n" ); document.write( "--------------
\n" ); document.write( "(1) $\"+a+%2B+b+=+80+\"$
\n" ); document.write( "(2) $\"+1%2Aa+%2B+.5%2Ab+=+50+\"$
\n" ); document.write( "-------------------
\n" ); document.write( "(1) $\"+b+=+80+-+a+\"$
\n" ); document.write( "Substitute this into (2)
\n" ); document.write( "(2) $\"a+%2B+.5%2A%28+80+-+a+%29+=+50+\"$
\n" ); document.write( "(2) $\"+a+%2B+40+-+.5a+=+50+\"$
\n" ); document.write( "(2) $\"+.5a+=+50+-+40+\"$
\n" ); document.write( "(2) $\"+.5a+=+10+\"$
\n" ); document.write( "(2) $\"+a+=+20+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+a+%2B+b+=+80+\"$
\n" ); document.write( "(1) $\"+b+=+60+\"$
\n" ); document.write( "There are 20 $1 coins and 60 $.50 coins
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+1%2A20+%2B+.5%2A60+=+50+\"$
\n" ); document.write( "(2) $\"+20+%2B+30+=+50+\"$
\n" ); document.write( "(2) $\"+50+=+50+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

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