SOLUTION: Shari wishes to place part of $ 12000 into a savings account earning 8 % simple interest and part into a savings account earning 7.25 % simple interest. The amount deposited at 8

Question 864854: Shari wishes to place part of $ 12000 into a savings account earning 8 % simple interest and part into a savings account earning 7.25 % simple interest. The amount deposited at 8 % is half the amount that is deposited at 7.25 %. How much should she invest in each if she wishes to earn $ 900 in interest for the year?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Part I 7.25% per annum ------------- Amount invested =x
Part II 8.00% per annum ------------ Amount invested = y
12000
Interest----- 900.00

Part I 7.25% per annum ---x
Part II 8.00% per annum ---y
Total investment
x + 1 y= 12000 -------------1
Interest on both investments
7.25% x + 8.00% y= 900
Multiply by 100
7.25 x + 8 y= 90000.00 --------2
Multiply (1) by -7.25
we get
-7.25 x -7.25 y= -87000.00
Add this to (2)
0 x 0.75 y= 3000
divide by 0.75
y = 4000
Part I 7.25% $ 8000
Part II 8.00% $ 4000

CHECK
8000 --------- 7.25% ------- 580.00
4000 ------------- 8.00% ------- 320.00
Total -------------------- 900.00

m.ananth@hotmail.ca

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