Question 218111
I can not figure out how to set this problem up.  I have tried to solve it multiple times.  Here is the question:

How can $4,000.00 be invested, part at 6% and the remainder at 10% so that the two investments will produce the same interest?

Thank you for your help.

Mandy


Let the amount invested at 6% be S. Then the amount invested at 10% = 4,000 - S


Since the interest amounts earned from both investments are equal, then we'll have:


.06S = .1(4,000 - S)


.06S = 400 - .1S


.06S + .1S = 400


.16S = 400


{{{S = 400/.16 = 2500}}}


Therefore, amount invested at S, or 6% = {{{highlight_green(2500)}}}, and the amount invested at 10% = {{{highlight_green(1500)}}}, calculated as $4,000 - $2,500.


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Check
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2,500 * .06 = $150

1,500 * .1 =  $150


Both interest amounts are the same.