Here is a formula where $y$ and $z$ are known $$ x = \frac{y-0.04z}{0.27z} $$ How would I work out $z$ when only $x$ and $y$ are known?
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This is a math site, not a finance, excel, or statistics site. We have sites for those other topics. I'd suggest you use them – Zach466920 Jun 24 '15 at 23:41
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Thanks - which one do you suggest? – Sunil Jun 24 '15 at 23:43
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2I'd go with Excel as your question has to do with a feature on that program :) – Zach466920 Jun 24 '15 at 23:44
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Thanks Zach. I'm just excel to show the problem.. what I need is a math formula to work out the answer. – Sunil Jun 24 '15 at 23:46
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In that case the economics/statistics stack exchange does the trick. It does depend on the formula being wanted though. – Zach466920 Jun 24 '15 at 23:47
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I can post there as well, however I thought if I needed an equation, Maths was the best place... is it not? – Sunil Jun 24 '15 at 23:49
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Not unless the equation is given beforehand, you want a derivation, or you need help solving it. – Zach466920 Jun 24 '15 at 23:52
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1Question updated. Does it make sense now? – Sunil Jun 24 '15 at 23:58
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Let us continue this discussion in chat. – Sunil Jun 25 '15 at 00:04
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$$x={{y-0.04 \cdot z} \over {0.27 \cdot z}}$$ Multiply the denominator to clear the fraction $$\Rightarrow 0.27 \cdot x\cdot z=y-0.04 \cdot z$$ Put the z's on the same side $$\Rightarrow 0.27 \cdot x\cdot z+0.04 \cdot z=y$$ Factor "out" the z $$z \cdot (0.27\cdot x+0.04)=y$$ Divide to get z $$z={{y} \over {0.27 \cdot x+.04}}$$ This is equivalent to $$z={{100 \cdot y} \over {27\cdot x+4}}$$
Hopefully you can generalize this method. Also, for future reference, make sure to post your own attempt at solution with your question.
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Zach466920
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Awesome - Thank you - I learned something today. I did find a small problem with the last step of the formala z = 100y / 27x + 4 .. The result was not the same as the previous step :) But Thanks anyway - this really helped :) – Sunil Jun 25 '15 at 00:38
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1Your welcome. To get the last formula, multiply both the top and bottom by 100. – Zach466920 Jun 25 '15 at 00:43