Sports betting compound interest running balance

[infradigensemble]

I'm not sure how to write this formula in excel. Thanks for taking a look.

Here it is algebraically: C*(A/B) - (A/B) + A = "new" A

With numbers: 1.0125*(.5/2)-(.5/2)+.5=.503

Then I want to insert the "new" A (or .503) into the formula and run the calculation 3000 times so that I can see the answer for each calculation.

For the sports bettors out there the "1.0125" represent -8000 moneyline multiplier. ".5" is a 50 cent sportbook balance which is then divided by two (b/c I am wagering half of my sportsbook balance with each wager), or .25. Then the winings from a won -8000 moneyline is added to the .5 and the new balance is .503.

So, the hypothetical is if I start with $0.50 and wager half my sportsbook balance on -8000 moneyline. My sportsbook balance is now at $0.503 of which I wager half on a -8000 moneyline...so on and so forth 3000 times.

Thanks for taking a look and let me know any questions!

[MrShorty]

It seems relatively straightforward, so I wonder if I am missing something. Here's how I would do it (assuming I understand everything correctly):
1) Enter B and C into convenient cells (Maybe A2 and B2).
2) Enter my starting value for A near the top of a column (0.5 entered into A5, maybe).
3) Enter my formula in the cell adjacent. =$B$2*A5/$A$2-A5/$A$2+A5 entered into B5. Note the mix of relative and absolute references.
4) In A6, make a copy of B5 using the simple =B5.
5) Copy B5 into B6.
6) Select A6:B6 and copy down 3000 rows.

Perhaps this is more of an algebra question? I notice that a little algebra simplifies the expression dramatically:
Anew=C*A/B-A/B+A -> use distributive property to factor out A
Anew=A*(C/B-1/B+1) -> when you substitute Anew in for A and work the algebra, you get a power expression
A(i)=A(0)*(C/B-1/B+1)^i

Now, you can enter A(0), C, B and i (3000) into convenient cells and enter that formula and get the result.

I'm not certain I understand the question. If I do, either of those approaches should work.

[MrShorty]

In addition, the FV() function can be used for appropriate compound interest problems. In this case, present value is your initial 0.5 (or -.5 depending on what you want negative and positive values to mean), the rate is (C/2-1/2), payment is 0, and nper is i (3000). =FV(C/2-1/2,3000,0,-0.5)

[infradigensemble]

Thanks McShorty. That solved it!