He said no one knows the answer, he didn't say there is no answer. He's right. Who's to say you're more right than us? Only a perfect being could prove who is right and who is wrong... and none of us have that attribute. In this case i'm a mathematics graduate (0.9... = 1 was actually covered in analysis), and a great many answers in mathematics are known and proven, they are called theorems. Its a construction entirely of logic, when something is proven it stays that way. Nothing can overturn it.