SOLUTION: Kevin had $10,000 he wanted to invest.He decided to put some of the money in an account paying 7% annual interest, and the rest of it in an account paying 4%. If he got $595 in int

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Question 769866: Kevin had $10,000 he wanted to invest.He decided to put some of the money in an account paying 7% annual interest, and the rest of it in an account paying 4%. If he got $595 in interest for the year, how much did he invest at 4%?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Part I 7.00% per annum ------------- Amount invested =x
Part II 4.00% per annum ------------ Amount invested = y
10000
Interest----- 595.00

Part I 7.00% per annum ---x
Part II 4.00% per annum ---y
Total investment
x + 1 y= 10000 -------------1
Interest on both investments
7.00% x + 4.00% y= 595
Multiply by 100
7 x + 4 y= 59500.00 --------2
Multiply (1) by -7
we get
-7 x -7 y= -70000.00
Add this to (2)
0 x -3 y= -10500
divide by -3
y = 3500
Part I 7.00% $ 6500
Part II 4.00% $ 3500

CHECK
6500 --------- 7.00% ------- 455.00
3500 ------------- 4.00% ------- 140.00
Total -------------------- 595.00

m.ananth@hotmail.ca