SOLUTION: A certin sum of money is invested at 10%. Twice that amount is invested at 8%. The total amount of intrest from both investments is $91. How much is invested at 8%.

Question 153020: A certin sum of money is invested at 10%. Twice that amount is invested at 8%. The total amount of intrest from both investments is $91. How much is invested at 8%.
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
Let x = amount invested at 8%
then
x/2 = amount invested at 10%
.
From the statement of the problem, we derive our equation of:
.10(x/2) + .08x = 91
.05x + .08x = 91
.13x = 91
x = 91/.13
x = $700 (amount invested at 8%)

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