Answer:
The woman invested $15,000 at 7% interest rate and $5,000 at 6% interest rate.
Step-by-step explanation:
We are given the following in the question:
Let x be the interest earned from 7% interest rate and y be the interest earned from 6% interest rate.
The woman invested has three times as much invested at 7% as she does at 6%.
Thus, we can write the equation:
[tex]x = 3y[/tex]
The total interest is $1,350.
Thus, we can write the equation:
[tex]1350 = \dfrac{7x}{100} + \dfrac{6y}{100}\\\\7x + 6y = 135000[/tex]
Solving the two equations by substitution method:
[tex]7(3y) + 6y = 135000\\27y = 135000\\y = 5000\\x = 3(5000) = 15000[/tex]
Thus, she invested $15,000 at 7% interest rate and $5,000 at 6% interest rate.
