document.write( "Question 1207428: For how many years will Prasad make payments on the $28,000 he borrowed to start his machine shop if he makes payments of $3400 at the end of every three months and interest is 8.08% compounded semi-annually? \n" ); document.write( "
Algebra.Com's Answer #845287 by ikleyn(52799)\"\" \"About 
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\n" ); document.write( "For how many years will Prasad make payments on the $28,000 he borrowed to start his machine shop
\n" ); document.write( "if he makes payments of $3400 at the end of every three months and interest is 8.08% compounded semi-annually?
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\n" ); document.write( "\n" ); document.write( "        The scheme of payments/compounding is non-standard and it is not totally clear how to it really works.\r
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\n" ); document.write( "\n" ); document.write( "        So,  in my solution I will make some assumptions,  but I am not sure if they are adequate.\r
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\n" ); document.write( "\n" ); document.write( "        In any case,  I will try.\r
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document.write( "It is equivalent to semi-annual payments on the loan with semi-annual payments of 2*3400 = 6800 dollars,\r\n" );
document.write( "while the loan is compounded semi-annually.\r\n" );
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document.write( "So, use the formula for semi-annual payments for a loan\r\n" );
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document.write( "    M = \"P%2A%28r%2F%281-%281%2Br%29%5E%28-n%29%29%29\"\r\n" );
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document.write( "where P is the loan amount; r = \"0.0808%2F2\" is the effective interest rate semi-annually;\r\n" );
document.write( "n is the number of payments (same as the number of semi-annual periods); \r\n" );
document.write( "M is the semi-annual payment of $6800.\r\n" );
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document.write( "In this problem  M = 6800;  P = $28000;  r = \"0.0808%2F2\".\r\n" );
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document.write( "Substitute these values into the formula and get for semi-annual payments\r\n" );
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document.write( "   6800 = \"28000%2A%28%28%280.0808%2F2%29%29%2F%281-%281%2B0.0808%2F2%29%5E%28-n%29%29%29\".\r\n" );
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document.write( "We should find \"n\" from this equation.\r\n" );
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document.write( "Divide both sides by 28000.  You will get\r\n" );
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document.write( "    \"6800%2F28000\" = \"%28%280.0808%2F2%29%29%2F%281-%281%2B0.0808%2F2%29%5E%28-n%29%29\",\r\n" );
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document.write( "or\r\n" );
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document.write( "    0.242857143 = \"%28%280.0808%2F2%29%29%2F%281-%281%2B0.0808%2F2%29%5E%28-n%29%29\".\r\n" );
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document.write( "It implies, step by step\r\n" );
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document.write( "    \"0.242857143%2A%282%2F0.0808%29\" = \"1%2F%281-%281%2B0.0808%2F2%29%5E%28-n%29%29\",\r\n" );
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document.write( "    6.011315417 = \"1%2F%281-%281%2B0.0808%2F2%29%5E%28-n%29%29\",\r\n" );
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document.write( "    \"1%2F6.011315417\" = \"1-%281%2B0.0808%2F2%29%5E%28-n%29\",\r\n" );
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document.write( "    0.166352941 = \"1-%281%2B0.0808%2F2%29%5E%28-n%29\",\r\n" );
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document.write( "    \"%281%2B0.0808%2F2%29%5E%28-n%29\" = 1 - 0.166352941,\r\n" );
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document.write( "    \"%281%2B0.0808%2F2%29%5E%28-n%29\" = 0.833647059,\r\n" );
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document.write( "    \"%281%2B0.0808%2F2%29%5En\" = \"1%2F0.833647059\",\r\n" );
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document.write( "    \"%281%2B0.0808%2F2%29%5En\" = 1.199548405.\r\n" );
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document.write( "Take logarithm base 10\r\n" );
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document.write( "    n*log(1+0.0808/2) = ln(1.199548405)\r\n" );
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document.write( "and find \"n\"\r\n" );
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document.write( "    n = \"log%28%281.199548405%29%29%2Flog%28%281%2B0.0808%2F2%29%29\" = 4.59.\r\n" );
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document.write( "From these calculations, I make the conclusion that input data in the problem are incorrect,\r\n" );
document.write( "since they lead to the non-integer number of semi-annual payments.\r\n" );
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