document.write( "Question 761805:  If 4 years of college are expected to cost $150,000 18 years from now, how much must be deposited now into an account that will average 8% annually in order to save the $150,000? By how much would your answer change if you expected 11% annually?  \n" ); document.write( "
Algebra.Com's Answer #463484 by josmiceli(19441)\"\" \"About 
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Let \"+P+\" = amount deposited now
\n" ); document.write( "Let \"+A+\" = the current savings
\n" ); document.write( "After 1st year,
\n" ); document.write( "\"+A+=+P+%2B+.08P+\"
\n" ); document.write( "---------------
\n" ); document.write( "After 2nd year,
\n" ); document.write( "\"+A+=+%28+P+%2B+.08P+%29+%2B+.08%2A%28+P+%2B+.08P+%29+\"
\n" ); document.write( "\"+A+=+%28+P+%2B+.08P+%29%2A%28+1+%2B+.08+%29+\"
\n" ); document.write( "\"+A+=+P%2A%28+1+%2B+.08+%29%2A%28+1+%2B+.08+%29+\"
\n" ); document.write( "----------------
\n" ); document.write( "After 3rd year,
\n" ); document.write( "
\n" ); document.write( "\"+A+=+P%2A%28+1+%2B+.08+%29%2A%28+1+%2B+.08+%29%2A%28+1+%2B+.08+%29+\"
\n" ); document.write( "\"+A+=+P%2A%28+1+%2B+.08+%29%5E3+\"
\n" ); document.write( "----------------------
\n" ); document.write( "So, this is the general rule:
\n" ); document.write( "\"+A+=+P%2A%28+1+%2B+.08+%29%5Et+\"
\n" ); document.write( "where \"t+\" = the number of years since initial deposit
\n" ); document.write( "given:
\n" ); document.write( "\"+A+=+150000+\"
\n" ); document.write( "\"+t+=+18+\"
\n" ); document.write( "\"+150000+=+P%2A%28+1+%2B+.08+%29%5E18+\"
\n" ); document.write( "\"+150000+=+P%2A1.08%5E18+\"
\n" ); document.write( "\"+150000+=+3.996P+\"
\n" ); document.write( "\"+P+=+37537.35+\"
\n" ); document.write( "$37,537.35 needs to be deposited now
\n" ); document.write( "---------------------------------
\n" ); document.write( "Rate = 11%
\n" ); document.write( "\"+150000+=+P%2A1.11%5E18+\"
\n" ); document.write( "\"+150000+=+6.544P+\"
\n" ); document.write( "\"+P+=+22923.33+\"
\n" ); document.write( "$22,923.33 needs to be deposited now\r
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