I am not sure two which "3 day notice" you are referring. I am assuming that you mean the demand for possession. There is no fixed time to respond to such letters, the letter typically will provide when you have to be out by. If this is a residential lease, you have a one-time right to pay the rent and make the dispo go away. If landlord accepts less than the full rent, you have a defense going forward if he continues with the action (commercial landlords can accept less than the full rent and still prosecute for eviction).
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