Question 729591
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A  customer purchased a car and financed $15,000. The customer borrowed part of the money from a bank 
charging 10% annual interest and the rest from a credit union at 9% annual interest. 
If the total interest from the year was $1430, how much was borrowed from the credit union?
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Let x be the amount borrowed from the credit union at 9% in dollars (the value under the problem's question).

Then the value borrowed from the bank at 10% is (15000-x) dollars.


Write an equation for the total annual interest

    0.09x + 0.1(15000-x) = 1430  dollars.    (1)


Simplify

    0.09x + 1500 - 0.1x = 1430,

    -0.09x - 0.1x = 1430 - 1500,

          -0.01x  =   -70,

               x  =  {{{(-70)/(-0.01)}}} = 7000.


Thus, 7000 dollars were borrowed from the credit union.


<U>ANSWER</U>.  $7000 were borrowed from the credit union.


<U>CHECK</U>.  The total annual interest is  {{{0.09*7000 + (15000-7000)*0.1}}} = 1430  dollars,   correct !
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Solved.