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I need to know where I am going wrong since I am getting the wrong answer

12 litres of water are poured into an aquarium of $50$ cm length , $30$ cm breadth and $40$ cm Height.How high in cm will the water rise. (Ans 8 cm)

Edit: So I was making some very illogical assumptions however according to advice given which suggested that I keep the changing dimension value variable I got the answer which is

$1000cm^3$ = $50 \times 30 \times x$ so $x = \frac{1000}{1500}$. so $1$ litre has height $\frac{1000}{1500} = \frac {2}{3}$ so $12$ litres will give $12 \times \frac{2}{3} = 8 cm$

MistyD
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  • I think a good start would be to ask whatever led you to write $50\times30\times40=5\times3\times4$ when it's patently not so. – Gerry Myerson Jul 24 '12 at 10:53
  • I agree that does not make sense – MistyD Jul 24 '12 at 10:55
  • Tips on solving this problem ? – MistyD Jul 24 '12 at 10:56
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    Which dimension (length, breadth, height) changes when you pour in the water? This is where the $x$ should go. The other two stay constant, so you have $x\cdot C_1 \cdot C_2$, which should match $12;l$. To make the match, you have to convert litres to $cm^3$... – draks ... Jul 24 '12 at 10:56
  • how did you get $12l$ ? – MistyD Jul 24 '12 at 11:01
  • Just some advice: I guess everybody here knows the answer but we want you to somehow get it yourself. Right now there are just so many things going wrong in your question. Where do the zeros go? In which units do you work? What is $x$? Why do you multiply $5x\cdot 3x\cdot 4x$? How do you conclude from $x=200$ that the height is $800$? First try to correct all those and I am sure somebody will help you then. – Simon Markett Jul 24 '12 at 11:10
  • @SimonMarkett I agree some assumptions were illogical I was treating the multiplicants as if they were ratios .. Though I fixed it thanks to draks – MistyD Jul 24 '12 at 11:24
  • @MistyD I put it as answer, so that you can accept it (if you like). This will prevent your questions from been bumped by the automatic system. Cheers... – draks ... Jul 24 '12 at 12:34

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Congratulation: your answer is correct!

draks ...
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  • You should have posted this as a CW answer, there is no real content in this and it only serves as a verification to the OP. – Asaf Karagila Jul 24 '12 at 14:01
  • @AsafKaragila Ok, but maybe you missed part of the story. Have a look at the comments and the revisions of the question. After alll, I'm still young and need the reputation...;-) – draks ... Jul 24 '12 at 14:40
  • draks, I saw that, and this is indeed what you should do when you solve something like that in the comments. However protocol suggests that if you didn't really answer beyond that, it's in good faith to make your answer CW. – Asaf Karagila Jul 24 '12 at 14:42
  • @AsafKaragila I'll promise I'll do next time... – draks ... Jul 24 '12 at 16:20