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I can't seem to figure this out.

The mass of 3 notebooks and 1 box is 610g. Each notebook is 250g lighter than the box. What is the mass of each notebook?

This seems to be $3(x-250)+x=610$. So, $3x-750+x=610\implies 4x-750=610\implies 4x=1360\implies x=1360/4 = 340$

Which seems to be impossible, since $3x$ (if each $x$ is $340$) is more than 610g.

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    +1 for showing your work. It allows a much more specific answer2012-07-09

1 Answers 1

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You set up the problem correctly, but $x$ stands for the mass of the box in your equation, not the mass of a notebook.

We have that $3\cdot(340-250)+340=3\cdot 90+340=270+340=610.$