document.write( "Question 1154337: Mark invested his money at 9% interest rate while Sarah invested her money at 5% interest rate. If Mark invested $1,000 more than what Sarah did and the combined amount of interest earned after a year is $790.00, how much did each person invest? \n" ); document.write( "

Algebra.Com's Answer #776738 by ramkikk66(644) $\"\"$ $\"About$

You can put this solution on YOUR website!

\n" ); document.write( "Ans:
\n" ); document.write( "Say Mark invested x dollars.
\n" ); document.write( "Then Sarah invested (x - 1000) dollars
\n" ); document.write( "Interest earned by Mark = $\"x+%2A+0.09\"$
\n" ); document.write( "Interest earned by Sarah = $\"%28x+-+1000%29+%2A+0.05\"$ = $\"0.05x+-+50\"$
\n" ); document.write( "Total interest = 790
\n" ); document.write( "So we have the equation
\n" ); document.write( " $\"0.09x+%2B+0.05x+-+50+=+790\"$
\n" ); document.write( "Moving constants to one side and variables to the other side\r
\n" ); document.write( "\n" ); document.write( " $\"0.14x+=+840\"$ or $\"x+=+6000\"$ \r
\n" ); document.write( "\n" ); document.write( "So Mark invested 6000 dollars and Sarah invested (6000 - 1000) = 5000 dollars.\r
\n" ); document.write( "\n" ); document.write( "Check
\n" ); document.write( "Interest for Mark = $\"6000+%2A+0.09+=+540\"$ \r
\n" ); document.write( "\n" ); document.write( "Interest for Sarah = $\"5000+%2A+0.05+=+250\"$ \r
\n" ); document.write( "\n" ); document.write( "Total interest = $\"540+%2B+250+=+790\"$ Check successful!\r
\n" ); document.write( "\n" ); document.write( "Ans: Mark = $6000, Sarah = $5000\r
\n" ); document.write( "\n" ); document.write( "

\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );