SOLUTION: MATRICES: Inverse Matrix and Applications Maria has $45,000 to invest and wants to receive a yearly interest of $4,290 of that money. She chose investments that pay 5%, 8%, and

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Question 1053097: MATRICES: Inverse Matrix and Applications
Maria has $45,000 to invest and wants to receive a yearly interest of $4,290 of that money. She chose investments that pay 5%, 8%, and 12% of simple interest. She wants the inverted amount at 12%, to be double the amount inverted at 8%. How much would Maria need to invest of each percent or rate?
Whenever I try to apply the formula for an inversed matrix, the answer is wrong. Help?
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MATRICES: Inverse Matrix and Applications
Maria has $45,000 to invest and wants to receive a yearly interest of $4,290 of that money.
She chose investments that pay 5%, 8%, and 12% of simple interest. She wants the inverted amount at 12%, to be double
the amount inverted at 8%. How much would Maria need to invest of each percent or rate?
Whenever I try to apply the formula for an inversed matrix, the answer is wrong. Help?
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1.  Inverted or INVESTED amount?  You often mix these words in the text.


2.  What is your goal? To apply inversion of matrices?
    
    The problem can be easily solved with more moderate and more appropriate tools 

    (Substitution or Elimination methods for a system of two equations in two unknowns).