SOLUTION: Some money is invested at 8% and twice as much at 5%. If the annual interest adds up to $720, how much is invested at each rate?

SOLUTION: Some money is invested at 8% and twice as much at 5%. If the annual interest adds up to $720, how much is invested at each rate?

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Question 1057279: Some money is invested at 8% and twice as much at 5%. If the annual interest adds up to $720, how much is invested at each rate?
Answer by jorel555(1290) (Show Source): You can put this solution on YOUR website!
Let n be the amount invested at 8%. Then the amount invested at 5% would be 2n. So:
.08n+2(.05)n=720
.18n=720
n=$4000 invested at 8%, $8000 invested at 5%. ☺☺☺☺
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