SOLUTION: Dan earned money from babysitting. He spent 1/4 of his money on a guitar and gave 1/4 of what was left to charity. He has $108 left. How much money did he begin with?

Question 672518: Dan earned money from babysitting. He spent 1/4 of his money on a guitar and gave 1/4 of what was left to charity. He has $108 left. How much money did he begin with?
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
Dan earned money from babysitting. He spent 1/4 of his money on a guitar and gave 1/4 of what was left to charity. He has $108 left. How much money did he begin with?
Let x = amount ($) he began with
then
x - (1/4)x - (1/4)(x - (1/4)x) = 108
x - x/4 - ((1/4)x - (1/4)(1/4)x) = 108
x - x/4 - (x/4 - (1/16)x) = 108
x - x/4 - (x/4 - x/16) = 108
x - x/4 - x/4 + x/16 = 108
multiplying both sides by 16:
16x - 4x - 4x + x = 1728
16x - 8x + x = 1728
8x + x = 1728
9x = 1728
x = $192

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