SOLUTION: Phoebe wishes to invest $20,000 part at 7% interest and the rest at 6.5% if her total income from the two investment for one year is $1370 how much should she invest at each rate?

Question 911078: Phoebe wishes to invest $20,000 part at 7% interest and the rest at 6.5% if her total income from the two investment for one year is $1370 how much should she invest at each rate?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Part I 7.00% per annum ------------- Amount invested =x
Part II 6.50% per annum ------------ Amount invested = y
20000
Interest----- 1370.00

Part I 7.00% per annum ---x
Part II 6.50% per annum ---y
Total investment
x + 1 y= 20000 -------------1
Interest on both investments
7.00% x + 6.50% y= 1370
Multiply by 100
7 x + 6.5 y= 137000.00 --------2
Multiply (1) by -7
we get
-7 x -7 y= -140000.00
Add this to (2)
0 x -0.5 y= -3000
divide by -0.5
y = 6000
Part I 7.00% $ 14000
Part II 6.50% $ 6000

CHECK
14000 --------- 7.00% ------- 980.00
6000 ------------- 6.50% ------- 390.00
Total -------------------- 1370.00

m.ananth@hotmail.ca

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