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Expert: - 10/9/2008


Question
Hello Scott: what is the excel formula for calculating yearly growth stated by month. i.e. last year's sales equal 100,000.  I expect 15% growth for the next year's sales $115,000.  What are my sales by month to achieve the $115,000?

Answer
If this is as simple as it might seem to be, all you have to do is take 15/12 [ or 5/4 ] and multiply by 100,000.  I have a feeling its not that simple, though.

If you're use to Excel,
A) Put 100,000 in A1 as currency.
B) Put =A1/A3 in A2 as currency, though it is undefined at first.
C) Put =((1+B3)^12-1)/B3 in A3.
D) Put 1 in B1 as a percent.
E) Put 0.15 in B2 (unless you read E, then you can put 15 in B2).
F) Put =(B1+B2)^(1/12)-1 in B3.
G) Put =A2 in A5.
H) Put =A5*(1+B$3)+A$5 in cell A6.  Copy this to cells A7:A16.
Amazingly, A16 should be the same A1.  Actually, I got this from
the basic formula for interest.

Basically, I have told you that to get a future amount, take the amount deposited each month * ((1+i)^n-1)/i where n is the number of periods and i is the interest for each period.  This is referred to as an annuity.  If you want a good explanation about how to deal with money and time, see http://www.kbapps.com/finance.html

If you need to rephrase the question (since I must not have got it right), you can ask me again in more detail.  You could also look at the document I sent you.

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Scott A Wilson

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I can answer any question in general math, arithetic, discret math, algebra, box problems, geometry, filling a tank with water, trigonometry, pre-calculus, linear algebra, complex mathematics, probability, statistics, and most of anything else that relates to math. I can even tell you it takes me over 2,000 steps to go a mile, but is that relevant?

Experience

Experience in the area; I have tutored people in the above areas of mathematics for almost two years in AllExperts.com. I have tutored people here and there in mathematics since before I received a BS degree almost 25 years ago. In just two more years, I received an MS degree as well, but more on that later. I tutored at OSU in the math center for all six years I was there. Most students offering assistance were juniors, seniors, or graduate students. I was allowed to tutor as a freshman. I tutored at Mathnasium for well over a year. I worked at The Boeing Company for over 5 years. I received an MS degreee in Mathematics from Oregon State Univeristy. The classes I took were over 100 hours of upper division credits in mathematical courses such as calculus, statistics, probabilty, linear algrebra, powers, linear regression, matrices, and more. I graduated with honors in both my BS and MS degrees. Past/Present Clients: College Students at Oregon State University, various math people since college, over 7,500 people on the PC from the US and rest the world.

Publications
My master's paper was published in the OSU journal. The subject of it was Numerical Analysis used in shock waves and rarefaction fans. It dealt with discontinuities that arose over time. They were solved using the Leap Frog method. That method was used and improvements of it were shown. The improvements were by Enquist-Osher, Godunov, and Lax-Wendroff.

Education/Credentials
Master of Science at OSU with high honors in mathematics. Bachelor of Science at OSU with high honors in mathematical sciences. This degree involved mathematics, statistics, and computer science. I also took sophmore level physics and chemistry while I was attending college. On the side I took raquetball, but that's still not relevant.

Awards and Honors
I earned high honors in both my BS degree and MS degree from Oregon State. I was in near the top in most of my classes. In several classes in mathematics, I was first. In a class of over 100 students, I was always one of the first ones to complete the test. I graduated with well over 50 credits in upper division mathematics.

Past/Present Clients
My clients have been students at OSU, people nearby, friends with math questions, and several people every day on the PC, and you're probably make one more.

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