Who says you can't make a buck in a bad economy?

As the pros on Wall Street took another pounding this week, Ashley Warren and her twin sister, Raina, made a small investment of their own and saw it grow 10-fold.

The pair, both juniors at the University of Pittsburgh, were declared the winners yesterday among three student teams who on Monday accepted a challenge designed to encourage entrepreneurial thought. Each team put up $5 of their own money. Then, over the next 70 hours or so, they were encouraged to use almost any creative means available on or off campus -- legal, of course -- to make their money grow.

Admittedly, there are less humbling ways to achieve wealth than wading into crowds outside the Petersen Events Center and Mellon Arena, calling out to strangers and waving a poster that reads, "Guess our Age. Win Cash!"

But, hey, this is college.

Using their $5 as backing for friendly wagers, the Warrens with help from a third team member, Gary Curtis, egged on passers-by to take a shot at the correct answer. Anyone right would get $1, and anyone wrong would be charged a buck.

"Initially, we were a bit nervous, but we just had fun with it," said Ashley Warren, 21, an English writing major who figured the idea made sense because people always get her and Raina's age wrong. "When it comes to making money, you can't be shy."

A second team used a laptop as collateral to obtain a $200 loan from another student, which then was used to buy holiday decorations at a pharmacy so they could be sold at a markup in the dorms. That brought in $39.50 in profit, after the $200 was repaid to the lender along with 10 percent of the profits from the sales.

A third team used hot chocolate donated from a friend, spent $2.88 of their $5 to buy cups, then tested just how much peers would pay.

"We called all of the people we knew and tried to talk them into buying hot chocolate for $1 per cup," said Adam Bechtel, 19, a sophomore from Slatington, Pa. "One guy just wanted a cup so we sold that to him for 25 cents.

"With other people, we had to negotiate the price because they either weren't able or weren't willing to pay the full $1 price," he said.

When the haggling was over, he and teammate Stephen Yen claimed $10.10 in earnings.

But the largest sum, $52, went to the Warrens, from Teaneck, N.J., who weren't afraid to change game plans when the "guess-my-age" routine stopped working.

Along the way, they discovered that supermarkets frown on strangers approaching customers at night. They also learned that the reception can be quite different outside a Pitt basketball game on campus than at a Penguins game on the edge of Downtown.

At the Pete, they made $30, and only two small children guessed right. But an hour outside Mellon left them with no takers.

"Some people saw our sign and just yelled out ages -- 'you're 30!' 'you're 15!' whatever -- but they didn't pay," Ashley Warren said.

After being turned away from the supermarkets, they encountered an elderly woman struggling with her bags and helped her carry them to an East End bus stop.

"She spontaneously gave us $1 each," the sisters wrote in a summary of their odyssey.

They passed around a can at a student meeting on campus Wednesday. And when all else failed, they called home to dad, who overnighted $10 to top off the total in time for yesterday's 10 a.m. deadline.

The challenge, in observance of Global Entrepreneurship Week, was supported by groups at Pitt, including the Institute for Entrepreneurial Excellence, part of the Katz Graduate School of Business. Teams could keep their modest profits, but institute staff said the exercise's larger benefit comes from teaching the importance of moving quickly on an opportunity.

"Putting yourself out there in front of strangers is huge. Being able to communicate your need and intent is huge," said Karma Edwards, member and student services manager. "Starting with very little capital is huge."

So is performing under pressure.

Just ask Chrissy Price, Lauren McMenamin and Andy Madden, who didn't make their first ornament sale until 7 p.m. on Wednesday, the final night of the competition. Within three hours, they had racked up $39.50 from wreaths, lights, window stickers, stockings and mugs.

"What I learned," said Ms. Price, 21, a senior economics and business major from Greensburg, "is that when it comes down to a deadline, we were able to make it all come together."