SOLUTION: a man invest 3,000 dollars at a certain rate and 4,000 dollars at rate of 2/3 as high. his annual income from the two investments 180 dollars. find the interest rates?

Question 957518: a man invest 3,000 dollars at a certain rate and 4,000 dollars at rate of 2/3 as high. his annual income from the two investments 180 dollars. find the interest rates?
Answer by macston(5194) (Show Source): You can put this solution on YOUR website!

i=certain rate
$3000i+$4000(2/3)i=180
$3000i+$2667i=180
5667i=$180 Divide each side by 5667
i=3.2% ANSWER 1: The certain interest rate was 3.2%
2/3i=2.1% ANSWER 2: The lower interest rate was 2.1%
CHECK
$3000i+$4000(2/3i)=$180
$3000(0.032)+$4000(0.021)=$180
$96+$84=$180
$180=$180

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