Based on that kind of growth, the company was able to raise $25 million in December from some of Silicon Valley’s top venture capitalists, including Kleiner Perkins Caufield & Byers.

Image Books are sorted at Chegg.com, named for a chicken-egg question. Flanking the chicken are Jim Safka, far right, C.E.O, and Aayush Phumbhra, a co-founder. Credit... Ozier Muhammad/The New York Times

“The textbook business was wildly inefficient,” said Mike Maples Jr., managing partner at Maples Investments, a fund that invests in young start-ups; it was one of Chegg’s first outside investors.

With demand for good deals on textbooks running high, Chegg’s success comes in large part from being able to address those inefficiencies. While Chegg primarily rents books, it is also essentially acting as a kind of “market maker,” gathering books from sellers at the end of a semester and renting  or sometimes selling  them to other students at the start of a new one. That provides liquidity to the market, said Yannis Bakos, associate professor of management at the Stern School of Business at New York University.

“The model is clever,” Professor Bakos said. “If they execute well, it will be an accomplishment.”

E-commerce was all the rage with investors during the Internet boom of the late 1990s. Of course, many start-ups failed. In recent years, most of the successful ideas in e-commerce have been refinements or variations of models that had been tried before.

In the case of Chegg and some budding competitors, the inspiration was Netflix.

“We benefit from the comfort zone that people have with renting things online from Netflix,” said Colin Barceloux, the co-founder of BookRenter.com, a Chegg rival that is also based in Silicon Valley.

Alan Bradford, a senior at Arizona State University, read about Chegg in a campus newspaper in 2008 and calculated that his bill for books that semester would have been $334 with Chegg, far less than the $657 he paid. Since then, he has ordered about a dozen textbooks from Chegg.

“Nobody likes paying for textbooks,” he said.

CHEGG is shorthand for “chicken and egg,” a reference to what Mr. Rashid called students’ quandary after graduation: they need experience to get a job, but can’t get experience without having a job.