In the wake of Rupert Murdoch's offer to buy Dow Jones & Co. for $5 billion, many have speculated about his motives -- about, as the New York Times put it on Sunday, "what makes Rupert run and why."

But when it comes to understanding the 76-year-old media baron's plans for the future, analysts would do well to consider something he said more than six years ago, in 2001.

The setting was a business and media conference in New York City. Murdoch, whose News Corp. was then in negotiations to acquire DirecTV from General Motors, was being interviewed in front of an audience by Charlie Rose.

When Rose asked Murdoch how he felt about his impending 70th birthday, Murdoch scowled and said, "Pretty bad."

Then, he pulled a folded piece of yellow legal paper from his breast pocket and revealed the time-conscious formula that drives his ambition.

Source: Rupert Murdoch

"I have lived for 613,000 hours," he said, consulting what appeared to be a handwritten tally. "201,000 of them were in childhood, youth, and thoroughly sort of inadequate education. That leaves 412,000. You take a third of that for sleep and rest. So I'm down to 275,000 hours.

"I take out a month for holidays, at least half a weekend, family time, evenings, etcetera, and you're down to at the very maximum a couple hundred thousand hours I've been at work.

"And then I go: 'What have I done? How much time have I wasted in endless meetings with no decisions? Industry conferences? Company conferences? Studying overlong reports?' Yeah, I guess I've wasted at least half my life.

"So that gets me down to perhaps 100,000 useful hours. Pretty bad figures. So if I'm pretty healthy and have a normal life expectancy -- I'm a bit optimistic -- I've got about another 175,000 hours to go, of which maybe I can spend 75,000 productively at work. Alright? Or 70,000 say.

"So I've just got to see that each one of those hours is well spent. And hopefully it won't all be spent talking to General Motors."

More than 53,000 hours have passed since Murdoch uttered those words, and he has done a lot more than talk to G.M.

In December 2003, he acquired a stake in DirecTV, the largest American satellite TV company; he has recently agreed to sell it to John Malone's Liberty Media.

In 2004, he and his wife, Wendi, bought a $44 million penthouse on Fifth Avenue (the former home of Laurance S. Rockefeller) that has been described as the most expensive apartment in New York.

He has used 20th Century Fox, the movie studio he bought in 1985 and revitalized, to bolster his Fox television network and his cable channels around the world.

In 2005, he bought MySpace.com for $580 million, and a few months later beat out Viacom Inc. again to acquire IGN Entertainment Inc., which runs video game Websites.

Now, he's trying to add a gem to his clutch of newspaper holdings by buying the publisher of the Wall Street Journal.

After all, time's a wasting. By his own reckoning, even with luck, Murdoch has only another 48,800 or so hours left of productive time.

by Amy Wallace

Chart by Zubin Jelveh/Portfolio.com

Photograph by Brad Barket/Getty Images