document.write( "Question 501884: Helen Weller invested $11,000. Part of it was invested a 5% interest and the rest was invested at 4% interest. How much was invested at each rate if $520 was earned in interest the first year? \n" ); document.write( "

Algebra.Com's Answer #338706 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"a\"$ = amount invested @ 5%
\n" ); document.write( "Let $\"b\"$ = amount invested @ 4%
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"+a+%2B+b+=+11000+\"$
\n" ); document.write( "(2) $\"+.05a+%2B+.04b+=+520+\"$
\n" ); document.write( "--------------------
\n" ); document.write( "(2) $\"+5a+%2B+4b+=+52000+\"$
\n" ); document.write( "Multiply both sides of (1) by $\"4\"$
\n" ); document.write( "and subtract (1) from (2)
\n" ); document.write( "(2) $\"+5a+%2B+4b+=+52000+\"$
\n" ); document.write( "(1) $\"+-4a+-+4b+=-+44000+\"$
\n" ); document.write( " $\"+a+=+8000+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+a+%2B+b+=+11000+\"$
\n" ); document.write( "(1) $\"+8000+%2B+b+=+11000+\"$
\n" ); document.write( "(2) $\"+b+=+3000+\"$
\n" ); document.write( "$8,000 was invested @ 5% and $3,000 was invested @ 4%
\n" ); document.write( "check answer:
\n" ); document.write( "(2) $\"+.05a+%2B+.04b+=+520+\"$
\n" ); document.write( "(2) $\"+.05%2A8000+%2B+.04%2A3000+=+520+\"$
\n" ); document.write( "(2) $\"+400+%2B+120+=+520+\"$
\n" ); document.write( "(2) $\"+520+=+520+\"$
\n" ); document.write( "OK \n" ); document.write( "

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