SOLUTION: An executive invests 22000, some at 7% and some at 6% annual interest. If he receives an annual return of 1420, how much is invested at each rate?

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Question 337409: An executive invests 22000, some at 7% and some at 6% annual interest. If he receives an annual return of 1420, how much is invested at each rate?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let A be the amount at 7%, B the amount at 6%.
A%2BB=22000
.
.
.
%287%2F100%29A%2B%286%2F100%29B=1420
2.7A%2B6B=142000
From eq. 1,
A=22000-B
Substitute into eq. 2,
7%2822000-B%29%2B6B=142000
154000-7B%2B6B=142000
-B=-12000
highlight%28B=12000%29
Then from eq. 1,
A%2B12000=22000
highlight%28A=10000%29