You invested part of $8000 in a stock that paid 12% annual interest. However, the rest of the money suffered a 5% loss. If the total annual income from both investments was $620, how much was invested at each rate?

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Let amt invested at 12% be "x" ; Interest is 0.12x dollars

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Amt invested at 5% = "8000-x" ; Interest is 0.05(8000-x) = 400-0.05x dollars

interest + interest = 620 dollars

0.12x + 400-0.05x = 620

0.07x = 220

x = $3142.86 (amt invested at 12%)

8000-x = $4857.14 ( amt invested at 5%)