document.write( "Question 57088: Helen Weller invested $15,000 in an account that pays 11% simple interest. How much additional money must be invested in an account that pays 14% simple interest so that the average return on the two investments amounts to 12%?
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Algebra.Com's Answer #38800 by Earlsdon(6294)![]() ![]() ![]() You can put this solution on YOUR website! Let x = the additional amount to be invested at 14%\r \n" ); document.write( "\n" ); document.write( "The interest on the initial $15,000 at 11% would be 0.11($15,000) \n" ); document.write( "The interest on the additional amount, $x at 14% would be 0.14($x) \n" ); document.write( "The sum of these two amounts of interest should come to 12% of ($15,000 + $x) or 0.12($15,000+$x). So...putting it all together. you can write:\r \n" ); document.write( "\n" ); document.write( "0.11($15000) + 0.14($x) = 0.12($15000+$x) Simplify this and solve for x. \n" ); document.write( "$1650 + 0.14x = 1800 + 0.12x Subtracting 0.12x from both sides, you get: \n" ); document.write( "1650 + 0.02($x) = $1800 Subtract $1650 from both sides. \n" ); document.write( "0.02($x) = $150 Finally, divide both sides by 0.02 \n" ); document.write( "x = $7500\r \n" ); document.write( "\n" ); document.write( "So Helen Weller should invest an additional $7,500 at 14% interest to obtain an average rate of return of 12% on the entire amount.\r \n" ); document.write( "\n" ); document.write( "Check: \r \n" ); document.write( "\n" ); document.write( "11% of $15,000 = 0.11($15,000) = $1,650 \n" ); document.write( "14% of $7,500 = 0.14($7,500) = $1,050 \n" ); document.write( "The sum: $1,650 + $1,050 = $2,700 total interest.\r \n" ); document.write( "\n" ); document.write( "12% of ($15,000 + $7,500) = 0.12($22,500) = $2,700 \n" ); document.write( " |