document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=870572>Question 870572</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Jenny is given $5000 at age 5. Her parents place it in a bank account earning 7% interest compounded quarterly. Write an equation to model the amount of money in the account. Find how much money Jenny will have at age 18<BR>\n" );
document.write( "Let x = number of interest periods		y = 5000 * 1.07x<BR>\n" );
document.write( "Let y = balance					y = 5000 * 1.0713<BR>\n" );
document.write( "Let a = initial deposit				y = 5000 * 2.4098<BR>\n" );
document.write( "Let b = interest rate				y = 12049.23<BR>\n" );
document.write( "y = a * bx					Jenny has $12,049.23 at age 18. <BR>\n" );
document.write( "y = 5000 * 1.07x<BR>\n" );
document.write( "What was my Error?<BR>\n" );
document.write( "I would like to know with these too. \r<BR>\n" );
document.write( "\n" );
document.write( "3.	The average number of minutes used on a cell phone each month in the year 2007 was 106 minutes. Since then, the number of minutes used each month has decreased by 2% each year. Write an equation to model the number of minutes used each month. Find the average number of minutes used on a cell phone in the year 2013. 	<BR>\n" );
document.write( "Given Answer:<BR>\n" );
document.write( "Let x = number of years since 2007				y = 106 * 1.02x<BR>\n" );
document.write( "Let y = number of minutes used each month 			y = 106 * 1.026<BR>\n" );
document.write( "Let a = number of minutes used each month in 2007		y = 106 * 1.12616<BR>\n" );
document.write( "Let b = the decay factor						y = 119.4<BR>\n" );
document.write( "y = a * bx							In 2013 the average number of<BR>\n" );
document.write( "y = 106 * 1.02x	minutes used each month was 119. \r<BR>\n" );
document.write( "\n" );
document.write( "4.	Todd deposited $7000 in a bank account earning 3% interest compounded yearly in 2008. Write an equation to model the amount of money in the account. Find how much money Todd will have in the account in 2015. <BR>\n" );
document.write( "Given Answer:<BR>\n" );
document.write( "Let x = number of interest periods		y = 7000 * 1.03x<BR>\n" );
document.write( "Let y = balance					y = 7000 * 1.0315<BR>\n" );
document.write( "Let a = initial deposit				y = 7000 * 1.55796<BR>\n" );
document.write( "Let b = interest rate				y = 10905.77<BR>\n" );
document.write( "y = a * bx					Todd has $10,905.77 in 2015. <BR>\n" );
document.write( "y = 7000 * 1.03x<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #524969 by </B><A HREF=/tutors/aboutme.mpl?userid=MathTherapy><B>MathTherapy(10552)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=MathTherapy><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=MathTherapy><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=524969\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <PRE STYLE=\"white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;\"><BR>\n" );
document.write( "I'll give you a hint for no. 1\r<BR>\n" );
document.write( "\n" );
document.write( "You're seeking the FUTURE VALUE of $5,000, invested for 13 (18 - 5) years, and compounded quarterly at a rate of 7%<BR>\n" );
document.write( "Future value formula: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A+=+P%281+%2B+r%2Fm%29%5Emt ALIGN=MIDDLE  ALT=\"A+=+P%281+%2B+r%2Fm%29%5Emt\"   DISABLED_style= \"max-width:90%; height:auto;\" >, with:<BR>\n" );
document.write( "P being principal or present value, or $5,000, in this case<BR>\n" );
document.write( "A being accumulated amount, or the future value of P<BR>\n" );
document.write( "r being the interest rate <BR>\n" );
document.write( "m being the NUMBER of ANNUAL compounding periods (4 in this case, since it's compounded quarterly)<BR>\n" );
document.write( "t being the time, in YEARS, that the money is invested </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );