Question 693792
 A person plans to invest three times as much in an account at 3% interest as in an account at 15% annual interest.
 How much should the person invest in each account to earn a total of $240 in one year? 
: 
let a = amt invested at 15%
then
3a = amt invested at 3%
:
.03(3a) + .15a = 240
.09a + .15a = 240
.24a = 240
a = 240/.24
a = $1000 invested at 15%
and
3(1000) = $9000 at 3%
:
:
Check this out, find how much interest earned by each investment:
.15*1000 = 150
.03*3000 =  90
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total int  240