Question 1202333
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David spent $75 of his money on some t-shirts. 
He spent 1/4 of the remaining money on some batteries. 
Given that he was left with 1/3 of his original sum of money left, 
how much money did David have at first?
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<pre>
Let x be the final amount;

then the starting amount was 3x, according to the problem.


After spending $75 on t-shirts, David left with (3x-75) dollars.


After spending 1/4 of remaining money on batteries, David remained with  {{{(3/4)*(3x-75)}}}  dollars.


        The problem says that  {{{(3/4)*(3x-75)}}} = x.


Simplify and find x

    9x - 225 = 4x

    9x - 4x = 225

       5x   = 225

        x   = 225/5 = 45.


He was left with 45 dollars.

Hence, he started with 3*45 = 135 dollars.    <U>ANSWER</U>
</pre>

Solved.