Question 1181288
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x nickels

x dimes

and the rest (500-2x) coins are quarters.



Keeping it in mind, you write the total money equation


    5x + 10x + 25(500-2x) = 7250  cents.


Simplify and find x


    5x + 10x - 50x + 25*500 = 7250

    25*500 - 7250 = 50x - 5x - 10x

    52500 = 35x

      x = {{{5250/35}}} = 150.


<U>ANSWER</U>.  The number of quarters is  500 - 2*150 = 200.
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Solved  (using one equation for one single unknown, ONLY).