Final answer:
The question addresses employment law relating to a 1974 court ruling about age requirements for Greyhound bus drivers. However, without further details of the ruling, the exact age limit cannot be specified. Employment law usually protects against age discrimination for those 40 and older.
Step-by-step explanation:
The question regarding the age requirement to be a driver for Greyhound Bus mentions a 1974 court ruling. It is likely related to employment law, which regulates the conditions of hiring and prohibits discrimination based on certain criteria, including age. The Age Discrimination in Employment Act (ADEA) of 1967 protects individuals who are 40 years of age or older from employment discrimination based on age. However, without the specific details of the court ruling mentioned, it's impossible to provide the exact age requirement set by the 1974 court ruling for Greyhound. Companies may have retirement or hiring age policies that have been challenged or upheld in court, but these are subject to change and can vary based on the company, the nature of the job, and current laws.