Urgent help: IB HL Math Portfolio type 2: Radiometric dating

[idontlikeib]

Hi guys,

I am sure somebody has done this portfolio and I really badly need help with it. I need to know how to model an equation. I know it is exponential decay but how do you create that equation.

and

How do you conjecture a model for 12 sided dice with each die showing a 12 is removed everytime they roll and the orignal number of dice are 100.

PLEASE HELP

I APPREICATE ANY INPUT

THANKS IN ADVANCE