All I can say is that opinions differ on that question, exhibiting a diversity similar to those on the shape of the Earth.
Marco Rubio, Senator from Flo Rida and Republican dream candidate of the future, probably wasn't really as stymied by ignorance as he pretends below:
GQ: How old do you think the Earth is?
Marco Rubio: I'm not a scientist, man. I can tell you what recorded history says, I can tell you what the Bible says, but I think that's a dispute amongst theologians and I think it has nothing to do with the gross domestic product or economic growth of the United States. I think the age of the universe has zero to do with how our economy is going to grow. I'm not a scientist. I don't think I'm qualified to answer a question like that. At the end of the day, I think there are multiple theories out there on how the universe was created and I think this is a country where people should have the opportunity to teach them all. I think parents should be able to teach their kids what their faith says, what science says. Whether the Earth was created in 7 days, or 7 actual eras, I'm not sure we'll ever be able to answer that. It's one of the great mysteries.
I'm going to make a wild guess that cowardice rather than ignorance was his cardinal flaw here. He dasen't rile up the ignoranti of the base. I will make another WG too - he's not an economist either.
UPDATE: Ross Douthat weighs in on the hazards of leading a party committed to denying big chunks of modern science and suggests cagier responses for politicians confronted with gotcha questions designed to expose that fact.