## re-arrange a basic formula

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d3ell
Posts: 1
Joined: Mon Apr 14, 2014 9:53 am
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### re-arrange a basic formula

Ok, so I feel a bit dumb not been able to do this myself, however I've already spent a couple of hours trying to work this out and it will probs take one of you guys 2min (if that!)

Im basically trying to re-arrange a formula that I use to work out my profit margin on a job.

to try and keep things simple i'll show you what I normally do and then explain what I want to do.

I first work out the price of my job, which for this example I will say this is £1000.00

I will then calculate what my labour and materials come too - for this example I will call this £700.00

I then subtract the Labour/materials from the price of the job, which gives me £300.00

I then divide the £300.00 by the price of the job which was £1000.00. This gives me 0.3 and as a percentage 30%

What im wanting to achieve is to constantly have the 30% as a percentage and the formula I use work out the price of the job, which at the minute I'm having to guess at and change the amount until I arrive at the 30% mark.

So the constants that I have are the £700.00 for labour and materials and the 30% that I want to total £1000.00

Does this make sense?

Thanks in advance if you can help!

D3ell

stapel_eliz
Posts: 1628
Joined: Mon Dec 08, 2008 4:22 pm
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Im basically trying to re-arrange a formula that I use to work out my profit margin on a job.
Perhaps, instead of starting with a price and then trying to work backwards to the costs, you might instead think about starting with the costs (which you know) and the percentage margin (which you have decided) and then work forwards to the price.

You know your cost C. You want to find the price P such that your cost C is 70% of the price P. So set up the "percent of" equation using the information that you have, and solve for the value that you need.