Whenever under the Financial Responsibility Act, the department fixes the amount of the security required of any person it shall notify the person of the amount so required by mailing to the person's address of record, a notice of security stating the amount of the security required, the date by which the security must be posted, and containing instructions on how to file the proof of financial responsibility. The date by which the security must be posted shall not be less than 20 nor more than 60 days following the date of mailing.