Question 127122: Bob invested $20,000, part at 14% and part at 13%. If the total interest at the end of the year is $2,720, how much did he invest at 14%?
Answer by ankor@dixie-net.com(22740)   (Show Source):
You can put this solution on YOUR website! Bob invested $20,000, part at 14% and part at 13%. If the total interest at the end of the year is $2,720, how much did he invest at 14%?
:
Let x = amt invested at 14%
:
It said the total invested was $20,000, therefore
(20000 - x) amt invested at 13%
:
.14x + .13(20000 - x) = 2720
:
.14x + 2600 - .13x = 2720
:
.14x - .13x = 2720 - 2600
:
.01x = 120
x = 
x = 12,000 invested at 14%
:
:
Check solution in original equation: (amt invested at 13% = 8000)
.14(12000) + .13(8000) =
1680 + 1040 = 2720; confirms our solution
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