document.write( "Question 1158483: I have 30 coins consisting of 20c coins a 5c coins and my total is $3.45 how many
\n" ); document.write( "20c and 5c coins do I have? \n" ); document.write( "

Algebra.Com's Answer #781428 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"+a+\"$ = number of 5c coins
\n" ); document.write( "Let $\"+b+\"$ = number of 20c coins
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\n" ); document.write( "(1) $\"+a+%2B+b+=+30+\"$
\n" ); document.write( "(2) $\"+5a+%2B+20b+=+345+\"$ ( in cents )
\n" ); document.write( "--------------------------------
\n" ); document.write( "(2) $\"+a+%2B+4b+=+69+\"$
\n" ); document.write( "Subtract (1) from (2)
\n" ); document.write( "(1) $\"+-a+-+b+=+-30+\"$
\n" ); document.write( "----------------------------
\n" ); document.write( " $\"+3b+=+39+\"$
\n" ); document.write( " $\"+b+=+13+\"$
\n" ); document.write( "and
\n" ); document.write( "(1) $\"+a+%2B+13+=+30+\"$
\n" ); document.write( "(1) $\"+a+=+17+\"$
\n" ); document.write( "------------------
\n" ); document.write( "number of 5c coins = 17
\n" ); document.write( "number of 20c coins = 13
\n" ); document.write( "-------------------------------
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+5a+%2B+20b+=+345+\"$
\n" ); document.write( "(2) $\"+5%2A17+%2B+20%2A13+=+345+\"$
\n" ); document.write( "(2) $\"+85+%2B+260+=+345+\"$
\n" ); document.write( "(2) $\"+345+=+345+\"$
\n" ); document.write( "OK \n" ); document.write( "

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