document.write( "Question 68120: Anna has 12 bills in her wallet, some $5 and some $10. The total value of the bills is $100. How many of eachbill does Anna have? \n" ); document.write( "
Algebra.Com's Answer #48398 by adamchapman(301)\"\" \"About 
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let the number of $5 bills be called 'a' and the number of $10 bills be called 'b'\r
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\n" ); document.write( "\n" ); document.write( "there are 12 bills in total, so:
\n" ); document.write( "a+b=12 ............(1)\r
\n" ); document.write( "\n" ); document.write( "the total value of all the bills is $100. So:
\n" ); document.write( "5a+10b-100 ............(2)\r
\n" ); document.write( "\n" ); document.write( "If we rearrange equation (1), we can get b=12-a, and replacin b in equation (2) with what we have just found:\r
\n" ); document.write( "\n" ); document.write( "5a+10(12-a)=100
\n" ); document.write( "5a+120-10a=100
\n" ); document.write( "-5a=-20
\n" ); document.write( "a=20/5
\n" ); document.write( "a=4\r
\n" ); document.write( "\n" ); document.write( "now replace the 'a' in equation (1) to get
\n" ); document.write( "4+b=12
\n" ); document.write( "b=8\r
\n" ); document.write( "\n" ); document.write( "Therefore Anna has 4 $5 bills and 8 $10 bills.\r
\n" ); document.write( "\n" ); document.write( "I hope this helps.\r
\n" ); document.write( "\n" ); document.write( "Please visit my website at www.geocities.com/quibowibbler\r
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