SOLUTION: donna invested part of her money at 12% and the rest at 15%. the income from both investment totaled P30,000. if she interchanged her investments, her income would have totaled P29

Question 890285: donna invested part of her money at 12% and the rest at 15%. the income from both investment totaled P30,000. if she interchanged her investments, her income would have totaled P29,400. how much did she invest at each income rate?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = amount invested @ 12%
Let = amount invested @ 15%
---------------------------------
(1)
You are also told that:
(2)
----------------------------
(1)
(2)
Divide both equations by
(1)
(2)
Multiply both sides of (1) by and
multiply both sides of (2) by , then
subtract ( 1) from (2)
(2)
(1)

and, since
(1)
(1)
(1)
--------------------
$100,000 was invested @ 12%
$120,000 was invested @ 15%
---------------------------
check:
(1)
(1)
(1)
OK
you can check (2)

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