Kind of a strange question to be honest, Basically you want an intake to bring cool fresh air in, and exhaust to vent used warmer air. You also need some sort of air blowing the plants to mimic wind, which promotes strong root growth, and a stronger stem to support the sites youll want.
have your fans as your exhaust and air will naturally intake through your open intake holes. If you can feel a wind through your intake, then your hole is not big enough.
I agree with what's been said before. However to answer your question, if you had more air coming in than going out the room would explode, if you had more air gong out than coming in you'd have a vacuum in the room