SOLUTION: I have a final exam tomorrow and these are two problems I am having a problem with on my review. If someone could show me how to do them it would be much appreciated. -Problem 1

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Question 865292: I have a final exam tomorrow and these are two problems I am having a problem with on my review. If someone could show me how to do them it would be much appreciated.
-Problem 1-
You inherit $2500 with the stipulation that for the first year the money must be involved into two stocks paying 10% and 6% annual interest, respectively. How much should be invested at the 6% rate if the total interest earned for the year is to be $221.92?
-Problem 2-
After an 8% increase in salary, Laurie makes 1016.50 per month. How much did she earn per month before the increase?
Any help would really be great thank you.
Found 2 solutions by richwmiller, mananth:
Answer by richwmiller(17219)   (Show Source): You can put this solution on YOUR website!
first problem
.06x+.10y=221.92,
x+y=2500
x=702., y=798.
second problem
1.08x=1016.50
x = 941.204 before the raise
Answer by mananth(16946)   (Show Source): You can put this solution on YOUR website!
Part I 6.00% per annum ------------- Amount invested =x
Part II 10.00% per annum ------------ Amount invested = y
2500
Interest----- 221.92

Part I 6.00% per annum ---x
Part II 10.00% per annum ---y
Total investment
x + 1 y= 2500 -------------1
Interest on both investments
6.00% x + 10.00% y= 221.92
Multiply by 100
6 x + 10 y= 22192.00 --------2
Multiply (1) by -6
we get
-6 x -6 y= -15000.00
Add this to (2)
0 x 4 y= 7192
divide by 4
y = 1798
Part I 6.00% $ 702
Part II 10.00% $ 1798

CHECK
702 --------- 6.00% ------- 42.12
1798 ------------- 10.00% ------- 179.80
Total -------------------- 221.92

m.ananth@hotmail.ca

suppose she gets 108 after increase originally she would have got 100
1016.50----------------------------------------?
(100/108)* 1016.50= $941.20
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