Question 210266
Interest. A high school student was able to save $8000 by working a part-time job every summer. He invested half the money in a money market account and half the money in a stock that paid three times as much interest as the money market account. After a year he earned $160 in interest. What were the interest rates of the money market account and the stock? 
Answer in percentages and round to one decimal place. 
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Let the money market rate be "r".
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Equation:
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interest + interest = interest
r*4000 + 3r*4000 = 160 dollars
15000r = 160
r = 0.01067... = 1.067%
3r = 0.032 = 3.2%
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Cheers,
Stan H.