Thread: Question about Probability calculation.

Hello all,
I'm working on probability project for french roulette and I've fall into some strange matematics out of my knoweledge and need your valuable help.

this is the info:
Z = 1/37
R = 18/37
ZR = Z * R = 0.0131482834

and this is the formula:


Here my problem is that I don't know how to calculate Z and R values to get the rezult shown in a formula above
all I need to know is how to sum (ZR)i part from formula, can you explain that to me please.

Here is what I have done so far, and it gives me wrong result:
pr(push) = Z * (Z / (1 - R)) * R = 0,0006920149

The original site where I found this is located here:
Ask the Wizard #259 - Wizard of Odds
If you have any question please ask me.

kind regards.

EDIT:
thank you, I solve it yeah

= 1/(1/Z * R) = 1,013323464

COOL