Amazon has deposited $250,000 in a maintenance fund for their trucks.

A study has suggested to not purchase new trucks, but rather set up this fund to pay for what is expected to be increasing maintenance costs over a time window of the next 10 years.

It has been estimated that truck costs next year will be $35,000, and that they will increase by some fixed amount year after year there-after. If Amazon uses an interest rate of 30%, what is the maximum fixed gradient of increase that can be supported by the maintenance fund?