JESS: Jess Rule Question - need help!

Hey Jess Users!  This is my first post, so I apologize for anything "noob"
that I say/do...

I'm very new to Jess.  I understand the basics but applying my knowledge for
the first time is proving more difficult than I anticipated.  Here is the
problem:

I need to set up a rule in Jess that calculates the cost of a benefit based
on age and enrollees.
*
Example:
The Benefit Configuration is "Employee $10k / Spouse $5k"
The enrollees are the employee (John Smith age 30) and spouse (Jane Smith
and 28).
The costs are calculated as follows:

Age               Employee            Spouse
18-29            11.55                    6.65
30-39            18.95                   10.35
40-49            38.35                   20.05*

*So John's cost is 18.95 and Jane's cost is 6.65 for a total of 25.60*.

Any advice would be greatly appreciated!

Thanks,

Derek Adams