math nerd help

[councilman24 37]

Okay, I have a bachelor's in chemistry, took lots of math, worked in industry as an analytical chemist in the pharmaceutical industry for 30 years and can't do this without a lot of angst and time.

Need to solve

(A x X) + (B x (y% x X) + (C x (z% x X) = TOT

for X where all other factors are know values selected by committee. Represents special assessment apportionment where A properties pay 100%(X), B pay one % of X, C pays another % of X and all gives a TOT dollar amount needed.

K-5th grade math for 6 years and my brain is flabby.

If someone can whip this out in 30 seconds like I out to be able to please help.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[RiggerLee 61]

x=tot/(a+by+cz)

Lee
lee@velocitysportswear.com
www.velocitysportswear.com

[councilman24 37]

Thanks Lee,

Obvious now but just too hard to turn on my brain these days.

I need to get a real job where I actually have to think.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[SethInMI 174]

www.wolframalpha.com is my goto equation solver.

Rigger lee posted the (trivial) solution, here is the input string to give the equation solver on that site:

solve a x + b y x + c z x = t for x

and it will give you Lee's answer. It can also solve MUCH harder equations.

It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

[councilman24 37]

I used to do this all the time, but like I said my brain is working.

I was reviewing an analytical procedure validation protocol written by a collegue who thought she could do no wrong, and reviewed and approved by her supervising PhD. It looked screwy and confused me for a few minutes. Then I did the simple unit analysis and realized it was completely wrong. The author had quit so I had to rewrite AND reexecute the validation work.

Same woman made a calculation error in another validation protocol and ended up with validation fom 1 to 15% of label instead of 10 to 150% of label. If she had payed attention to the scale on the autoscaled detector traces she would have seen all the peaks were too small. The auto scaled peaks of course were full scale. We were two days from filing the procedure with the FDA and I had to scramble to redo that one too. 5 days before I was being laid off for ever.

Anyway, thanks, and yes its trivial but so is my brain today.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE