Question 334382
Arlene purchased some municipal bonds yielding 7% annually and some certificates of deposit yielding 9% annually. 
If Arlene's investment amounts to $11,000 and the annual income is $810, how much money is invested in bonds and how much is invested in certificates of deposit?
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Quantity Equation: x + y = 11000
Income Equation::0.07x+0.09y = 810
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Multiply thru the Quantity Equation by 7
Multiply thru the Income Equation by 100
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7x + 7y = 77000
7x + 9y = 81000
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Subtract 1st from 2nd and solve for "y":
2y = 4000
y = $2000 (amt. invested in 9% CD's)
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Cheers,
Stan H.