It’s an obvious question — What keeps Barnes & Noble from going the way of Borders?

The answer is – it still makes money selling books. And might keep doing so with a bit of judicious trimming.

Barnes & Noble CEO Mitchell Klipper told the Wall Street Journal in January that the chain will close up to a third of its stores within 10 years. At its peak the chain had 726 stores (2008), now has 689, and expects to slim down to 450-500 stores.

Yes, sales are down, but the CEO says most of the stores are profitable. In fact, those profits are offsetting losses in the company’s Nook division.

That’s why Barnes & Noble founder Leonard Riggio would like to buy the bookstores and e-commerce business from the company. The public company would keep B&N’s share of the Nook business and its college bookstores.

That’s how it works in the printing business. “I’ll buy the black ink and leave you the red ink.”

[Thanks to John Mansfield for the story.]