SOLUTION: how long will it take 4000$ to double itself if it is invested at 8% simple interest?

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Question 352502: how long will it take 4000$ to double itself if it is invested at 8% simple interest?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

A=P%2BPrt Start with the simple interest formula.


8000=4000%2B4000%2A0.08%2At 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%2B320%2At Multiply 4000 and 0.08 to get 320.


8000-4000=320%2At Subtract 4000 from both sides.


4000=320%2At Combine like terms.


4000%2F320=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).


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Jim