Flat Rates in Rate Tables

Hi All,

How to implement the following scenarios in Rate Table / Calculation Sheets.

Case1:

Upto 15kg - USD 100 (Fixed)

15-30kg    - USD 10 per KG

31-50kg    - USD 12 per KG

51+ kg      - USD 13 per KG.

Case2:

1 Quantity - 100 USD

Every addnl Quantity - 80 USD

Please help on how to create Rate Table / Calculation Sheets for the above cases.

Thanks,

Michael M