SOLUTION: You invested $7000 in two accounts paying 8% and 7% annual interest, respectively. If the total interest earned for the year was $500, how much was invested at each rate? Let de

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Question 704280: You invested $7000 in two accounts paying 8% and 7% annual interest, respectively. If the total interest earned for the year was $500, how much was invested at each rate?
Let denote the amount of money invested at 8%. Find an expression in terms of for the amount invested at 7%.

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Part I 8.00% per annum ------------- Amount invested =x
Part II 7.00% per annum ------------ Amount invested = y
7000
Interest----- 500

Part I 8.00% per annum ---x
Part II 7.00% per annum ---y
Total investment
x + 1 y= 7000 -------------1
Interest on both investments
8.00% x + 7.00% y= 500
Multiply by 100
8 x + 7 y= 50000.00 --------2
Multiply (1) by -8
we get
-8 x -8 y= -56000.00
Add this to (2)
0 x -1 y= -6000
divide by -1
y = 6000
Part I 8.00% $ 1000
Part II 7.00% $ 6000



CHECK
1000 --------- 8.00% ------- 80.00
6000 ------------- 7.00% ------- 420.00
Total -------------------- 500.00

m.ananth@hotmail.ca