SOLUTION: A retired couple invested part of $11,400 at 6% interest and the rest at 7.5%. If their annual income from these investments is $783. Find the invested part at each rate?

Question 521852: A retired couple invested part of $11,400 at 6% interest and the rest at 7.5%. If their annual income from these investments is $783. Find the invested part at each rate?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
A retired couple invested part of $11,400 at 6% interest and the rest at 7.5%. If their annual income from these investments is $783. Find the invested part at each rate?
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Equations:
x + y = 11,400
0.075x + 0.06y = 783
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Multiply thru 1st equation by 75
Multiply thru 2nd equation by 1000
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75x + 75y = 75*11400
75x + 60y = 783000
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Subtract and solve for "y":
15y = 72000
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y = $4800 (amt invested at 6%)
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Solve for "x":
x + y = 11,400
x + 4800 = 11,400
x = $6600 (amt invest at 7.5%)
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Cheers,
Stan H.
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