SOLUTION: Susan inherited $12,000 and invested some of it in an account earning 5% simple interest and put the rest in an account earning 8% simple interest. If she earned a total of $810 in

Question 865364: Susan inherited $12,000 and invested some of it in an account earning 5% simple interest and put the rest in an account earning 8% simple interest. If she earned a total of $810 in interest after 1 year, how much did she invest in each account?
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
Part I 5.00% per annum ------------- Amount invested =x
Part II 8.00% per annum ------------ Amount invested = y
12000
Interest----- 810.00

Part I 5.00% per annum ---x
Part II 8.00% per annum ---y
Total investment
x + 1 y= 12000 -------------1
Interest on both investments
5.00% x + 8.00% y= 810
Multiply by 100
5 x + 8 y= 81000.00 --------2
Multiply (1) by -5
we get
-5 x -5 y= -60000.00
Add this to (2)
0 x 3 y= 21000
divide by 3
y = 7000
Part I 5.00% $ 5000
Part II 8.00% $ 7000

CHECK
5000 --------- 5.00% ------- 250.00
7000 ------------- 8.00% ------- 560.00
Total -------------------- 810.00

m.ananth@hotmail.ca

RELATED QUESTIONS
Last year, Dan had $10,000 to invest. He invested some of it in an account that paid 5%... (answered by josgarithmetic,greenestamps)

Barneys money earned $204 in interest after 1 year. He invested some of is money in an... (answered by richwmiller)

Susan is planning on investing her $1,600 bonus, putting some in an account earning 6%... (answered by Mathtut)

Last year, Ivanna had $10,000 to invest. She invested some of it in an account that paid... (answered by josgarithmetic)

Last year, Carlos had $30,000 to invest. He invested some of it in account that paid 10%... (answered by greenestamps)

Beth is planning on investing her $12,000 bonus, putting some in an account earning 7%... (answered by macston)

Mahmoud invested 6000 in two accounts, some of it at 2% simple interest, the rest in an... (answered by josmiceli)

Last year, Michael had $20,000 to invest. He invested some of it in an account that paid... (answered by ikleyn)

Last year, Kareem had $10,000 to invest. He invested some of it in an account that paid... (answered by ikleyn)