Question 649565:  Laura splits an investment of $35000, a portion earning simple interest at a rate of 4.3 % per year and the rest earning at a rate of 6.3 % per year in such a way that the return on the total investment is 5.70%. How much money was invested at each rate? (Round to the nearest 100 dollars.) 
 
At rate 4.3 % :   
At rate 6.3 % : 
 
I really need help solving this problem. Thank you. 
 Answer by MathTherapy(10557)      (Show Source): 
You can  put this solution on YOUR website!  
Laura splits an investment of $35000, a portion earning simple interest at a rate of 4.3 % per year and the rest earning at a rate of 6.3 % per year in such a way that the return on the total investment is 5.70%. How much money was invested at each rate? (Round to the nearest 100 dollars.) 
 
At rate 4.3 % :   
At rate 6.3 % : 
 
I really need help solving this problem. Thank you.
 
 
Let amount invested at 4.3% be F 
Then amount invested at 6.3% = 35,000 – F 
Since return on investment = 5.7%, then: .043F + .063(35,000 – F) = .057(35,000) 
.043F + 2,205 - .063F = 1,995 
.043F - .063F = 1,995 - 2,205  
- .02F = - 210
 
 
F, or amount invested at 4.3% =  , or  , or $ 
 
 
Amount invested at 6.3% = $35,000 – 10,500, or $ 
 
 
I’ll leave the check up to you!!
 
 
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