document.write( "Question 1202333: 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? \n" ); document.write( "
Algebra.Com's Answer #837073 by math_tutor2020(3817) ![]() You can put this solution on YOUR website! \n" ); document.write( "Answer: $135\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Work Shown:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = starting amount of money \n" ); document.write( "x-75 = amount left after buying the shirts \n" ); document.write( "(1/4)*(x-75) = amount spent on batteries \n" ); document.write( "(3/4)(x-75) = amount leftover after buying the batteries\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Note that 1/4 + 3/4 = 1 = 100% of his money\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "That last expression is set equal to (1/3)x because David is left with 1/3 of his original money.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(3/4)(x-75) = (1/3)x \n" ); document.write( "12*(3/4)(x-75) = 12*(1/3)x \n" ); document.write( "9(x-75) = 4x \n" ); document.write( "9x-675 = 4x \n" ); document.write( "9x-4x = 675 \n" ); document.write( "5x = 675 \n" ); document.write( "x = 675/5 \n" ); document.write( "x = 135 \n" ); document.write( "David started off with $135\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Check: \n" ); document.write( "Start = 135 \n" ); document.write( "Buy the shirts: 135-75 = 60 dollars left \n" ); document.write( "(1/4)*60 = 15 dollars spent on batteries \n" ); document.write( "60-15 = 45 dollars at the end \n" ); document.write( "45/135 = 1/3 of what he started with \n" ); document.write( "The answer is confirmed. \n" ); document.write( " \n" ); document.write( " |