You have a 4 second segment of continuous data. You sample it at 500 Hz. How much would you gain in terms of frequency resolution if you had sampled at 750 Hz?

I was given this question in an assignment, I am a complete novice in these areas and wasn't sure how to go about answering it. can anyone help me? You have a 4 second segment of continuous data. You sample it at 500 Hz. How much would you gain in terms of frequency resolution if you had sampled at 750 Hz. Explain your answer.