GingerAle
Oct 14, 2018

#2**+5 **

I found one of your questions (I’m a blŏŏdy mind reader). It wasn’t yesterday, though.

Here’s the link.

http://web2.0calc.com/questions/why-am-i-sooooo-dumb

DragonSlayer answered it. Your current post is proof that his answer is wrong.

You should make an account. Here’s a list of user names you can choose from.

http://web2.0calc.com/questions/help-me_37#r4

**Does anyone here, other than me, miss our Troll?**

GingerAleAug 6, 2016

#14**+5 **

Thank you for the reply. I actually did find these numbers, but not directly. I did this by creating a spread sheet starting with a value of X and incremented each successive value of X by multiplying by 1.05. I also kept a running total. When the 10th value = 100,000,000, I knew that was the correct starting value. (The 10th value was actually = 100,000,000.04 – a rounding error, I guess). It took about a half-hour to zero in on the starting value.

What I didn’t know how to do was find the starting value directly. Even though it is not an interest rate problem, I tried using the present value formula, with the interest rate set at 105% per year with a FV set at 100,000,000. . . . Nope! Not even close. I tried adjusting the “interest rate” by using a harmonic average, geometric average, and the median. Nope!

Now that you‘ve pointed out this is a geometric series, I read the wiki on this subject and found the formula relating to this.

https://en.wikipedia.org/wiki/Geometric_series#Economics

\(s=a{\frac {1-r^{n}}{1-r}}\)

After solving the formula for (a), the solution instantly popped out, like a “Where’s Wally” character.

Thanks guest. I always enjoy finding Wally.

GingerAleJun 18, 2016