The answer shall admit or deny the allegations of fact contained in each paragraph of the petition, and all such allegations, other than those as to the amount of damages, are admitted if not denied in the answer. If the defendant is without knowledge or information sufficient to justify a belief as to the truth of an allegation of fact made in the petition, he shall so state and this shall have the effect of a denial. Denials shall fairly meet the substance of the allegations denied. When the defendant intends in good faith to deny only a part of or to qualify an allegation of fact, he shall admit so much of it as is true and material and shall deny or qualify the remainder.