SOLUTION: Katie invested a total of $4000, part at 3% simple interest and part at 4% simple interest. At the end of 1 year, the investments had earned $136 interest. How much was invested at

Question 1092177: Katie invested a total of $4000, part at 3% simple interest and part at 4% simple interest. At the end of 1 year, the investments had earned $136 interest. How much was invested at each rate?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Use

(1)
--------------------------
and

----------------------------

----------------------------------

(2)
Plug (1) into (2)
(2)
(2)
(2)
and

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$2,400 is invested @ 3%
$1,600 is invested @ 4%
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check:
(1)
(1)
(1)
and
(2)
(2)
(2)
-------------------------

OK

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