Of course we know the answer, because Noah was righteous in the sight of God.
Gen 7:1 “And the LORD said unto Noah, Come thou and all thy house into the ark; for thee have I seen righteous before me in this generation.”
But the question is how did Noah obtain “Righteousness”?
How is anyone, in the Bible declared righteous?
Heb 11:7 “By faith Noah, being warned of God of things not seen as yet, moved with fear, prepared an ark to the saving of his house; by the which he condemned the world, and became heir of the righteousness which is by faith.”
Rom 4:1-8 “What shall we say then that Abraham our father, as pertaining to the flesh, hath found? 2For if Abraham were justified by works, he hath whereof to glory; but not before God. 3For what saith the scripture? Abraham believed God, and it was counted unto him for righteousness. 4Now to him that worketh is the reward not reckoned of grace, but of debt. 5But to him that worketh not, but believeth on him that justifieth the ungodly, *his faith is counted for righteousness*. 6Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works, 7Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered. 8Blessed is the man to whom the Lord will not impute sin.”
Rom 11:5-6 “Even so then at this present time also there is a remnant according to the election of grace. 6And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then it is no more grace: otherwise work is no more work.”
Our righteousness can be only from God through Christ.
Phil 3:9 “And be found in him, not having mine own righteousness, which is of the law, but that which is through the faith *of* Christ, *the righteousness which is of God* by faith:”
Tit 3:5-6 “Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost; 6Which he shed on us abundantly through Jesus Christ our Saviour;”
2 Cor 5:21 “For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.”
Eph 2:8 “For by grace are ye saved through faith; and that not of yourselves: it is the gift of God:”
Isa 61:10 “I will greatly rejoice in the LORD, my soul shall be joyful in my God; for he hath clothed me with the garments of salvation, he hath covered me with the robe of righteousness, as a bridegroom decketh himself with ornaments, and as a bride adorneth herself with her jewels.