Swami Vivekananda offers his opinion on this topic in his lecture The Religion We Are Born In:
In the Puranas we find many things which do not agree with the Vedas. As for instance, it is written in the Puranas that someone lived ten thousand years, another twenty thousand years, but in the Vedas we find :— "Man lives indeed a hundred years."
Which are we to accept in this case? Certainly the Vedas.