Question 800172
$4,000 is invested at 3% interest. How much money must be invested at 5% interest so that the total interest from the two investments is $195 after a year? 
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Quantity Equation: t + f = 4000
Interest Equation: 3t+5f = 19500
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Modify for elimination::
3t + 3f = 12000
3t + 5f = 19500
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Subtract and solve for "f":
2f == 7500
f = $3750 (amt. invested at 5%)
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Solve for "t":
t + 3750 = 4000
t = $250 (amt. invested at 3%)
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Cheers,
Stan H.
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