SAN FRANCISCO (AP) — Even Apple is surprised by the success of the iPad.CEO Tim Cook said Wednesday that, "The momentum behind (the) iPad has been incredible and has surprised just about everyone."He says the number of iPads sold in the last three months of 2011 was greater than any single vendor sold of traditional PCs. Apple sold 15.43 million iPads in that quarter to bring the total to 55 million.He says the iPad is "reinventing portable computing and ... outstripping the wildest of predictions."Apple revealed a new iPad model at Wednesday's event in San Francisco. It has a speedier processor, a sharper screen and an option for faster wireless broadband access. It will go on sale March 16 starting at $499.