document.write( "Question 1144054: A 1000 pound fund is loaned at 5% interest for 100 years. After 100 yrs., the fund would be worth over 100 times the original amount. Calculate amt.\r
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\n" ); document.write( "\n" ); document.write( "Interest at 5% = .05\r
\n" ); document.write( "\n" ); document.write( "Not sure how to solve. Non-homework.\r
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Algebra.Com's Answer #765047 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
the general formula for this type of problem is f = p * (1 + r) ^ n.
\n" ); document.write( "f is the future value
\n" ); document.write( "p is the present value
\n" ); document.write( "r is the interest rate per time period.
\n" ); document.write( "n is the number of time periods.\r
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\n" ); document.write( "\n" ); document.write( "your time period is in years.
\n" ); document.write( "n is equal to 100 years.
\n" ); document.write( "r is equal to .05 per year.
\n" ); document.write( "p is equal to 1000 pounds.
\n" ); document.write( "you want to find f.\r
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\n" ); document.write( "\n" ); document.write( "your formula becomes f = 1000 * (1 + .05) ^ 100.\r
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\n" ); document.write( "\n" ); document.write( "solve for f to get f = 131,501.2578\r
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\n" ); document.write( "\n" ); document.write( "that is indeed greater than 100,000 which is equal to 1,000 * 100.\r
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\n" ); document.write( "\n" ); document.write( "your statement is therefore accurate.\r
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\n" ); document.write( "\n" ); document.write( "if you wanted to find out when you actually made 100 times your original amount, you would do the following.\r
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\n" ); document.write( "\n" ); document.write( "f = 100,000
\n" ); document.write( "p = 1,000
\n" ); document.write( "r = .05
\n" ); document.write( "n = what you want to find.\r
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\n" ); document.write( "\n" ); document.write( "the same formula is used.
\n" ); document.write( "it becomes 100,000 = 1,000 * (1 + .05) ^ n
\n" ); document.write( "you want to find n.
\n" ); document.write( "you would divide both sides of this equation by 100 to get:
\n" ); document.write( "100,000 / 1,000 = (1 + .05) ^ n
\n" ); document.write( "simplify to get 100 = (1 + .05) ^ n
\n" ); document.write( "take the log of both sides of this equation to get:
\n" ); document.write( "log(100) = log((1 + .05) ^ n)
\n" ); document.write( "since log((1 + .05) ^ n) = n * log(1 + .05), the formula becomes:
\n" ); document.write( "log(100) = n * log(1.05)
\n" ); document.write( "divide both sides of this equation by log(1.05) to get:
\n" ); document.write( "log(100) / log(1.05) = n
\n" ); document.write( "solve for n to get n = 94.38726564\r
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\n" ); document.write( "\n" ); document.write( "the future value of your investment should be exactly 100 times the initial investment in 94.38726564 years.\r
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\n" ); document.write( "\n" ); document.write( "confirm this is true by replacing n in the original equation with that value to get:
\n" ); document.write( "f = 1,000 * (1 + .05) ^ 94.38726564
\n" ); document.write( "solve for f to get f = 100,000.\r
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\n" ); document.write( "\n" ); document.write( "the solution to when you would actually get exactly 100 times your initial investment is confirmed to be good.\r
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\n" ); document.write( "\n" ); document.write( "you can also graph the equation to visually see what happens to your investment.
\n" ); document.write( "for graphing purposes, the equation becomes y = 1000 * 1.05 ^ x.
\n" ); document.write( "this is what the graph looks like.\r
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\n" ); document.write( "\n" ); document.write( "as you can see, your investment really starts taking off after about the 60th year.
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