Question 352502


{{{A=P+Prt}}} Start with the <a href=http://www.mathwords.com/s/simple_interest.htm>simple interest formula</a>.



{{{8000=4000+4000*0.08*t}}} Plug in {{{A=8000}}} (Double the amount of the initial investment of $4000), {{{P=4000}}}, and {{{r=0.08}}} (the decimal equivalent of 8%).



{{{8000=4000+320*t}}} Multiply {{{4000}}} and {{{0.08}}} to get {{{320}}}.



{{{8000-4000=320*t}}} Subtract {{{4000}}} from both sides.



{{{4000=320*t}}} Combine like terms.



{{{4000/320=t}}} Divide both sides by {{{320}}} to isolate 't'.



{{{12.5=t}}} Divide.



{{{t=12.5}}} Rearrange the equation.



So it will take about 12.5 years for an investment of $4000 to double to $8000 with an interest rate of 8% (using simple interest).



If you need more help, email me at <a href="mailto:jim_thompson5910@hotmail.com?Subject=Algebra%20Help">jim_thompson5910@hotmail.com</a>


Also, feel free to check out my <a href="http://www.freewebs.com/jimthompson5910/home.html">tutoring website</a>


Jim