document.write( "Question 1162050: Chapter: Amount of Annuity\r
\n" ); document.write( "\n" ); document.write( "You wish to purchase a house for $200,000 in 12 years. You can invest your money at 5%/a compounded semiannually. How much do you need to invest every 6 months, starting in 6 months, so that you will have $200,000 at the time of your last deposit?
\n" ); document.write( "

Algebra.Com's Answer #785747 by greenestamps(13203)\"\" \"About 
You can put this solution on YOUR website!


\n" ); document.write( "Future value annuity formula:

\n" ); document.write( "\"A+=+P%28%281%2B%28r%2Fn%29%29%5E%28nt%29-1%29%2F%28r%2Fn%29\"

\n" ); document.write( "A = future value
\n" ); document.write( "P = periodic contribution
\n" ); document.write( "r = annual interest rate
\n" ); document.write( "n = number of compounding periods per year
\n" ); document.write( "t = time (years)

\n" ); document.write( "Note those parameter definitions mean

\n" ); document.write( "r/n = periodic interest rate
\n" ); document.write( "1+r/n = periodic growth factor
\n" ); document.write( "nt = number of compounding periods

\n" ); document.write( "In this example,

\n" ); document.write( "A = 200,000
\n" ); document.write( "P = the unknown
\n" ); document.write( "r = 5% = .05
\n" ); document.write( "n = 2
\n" ); document.write( "t = 12
\n" ); document.write( "r/n = .025
\n" ); document.write( "1+r/n = 1.025
\n" ); document.write( "nt = 24

\n" ); document.write( "I'll let you get the practice in doing the calculations....

\n" ); document.write( "It's very easy to get ridiculous answers if you get decimal points or parentheses in the wrong place; make sure your answer makes sense.

\n" ); document.write( "You should get an answer of a little under $6200. That makes sense because not counting the interest $6200 every 6 months for 12 years is $6200*24 = $148,800; it's reasonable that the accrued interest will bring that up to the desired $200,000.

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